1939 guns took me several days:
398 37mm wz.18 [inf gun] - name should be wz.16 and a secondary weapon should be French 112 Lebel
409 65mm Mtn Gun - ending date should be 10/39 (10/49, an evident typo). Radio should be 91(92) - very rare, used only by mountain units.
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75 mm artillery:
Only two types of 75mm pieces were used by the Polish by 1939, and both were field guns: wz.1897 (French) used by artillery regiments and wz.02/26 used by cavalry and in infantry regiments. None were specifically assigned to AT role.
You can read more at
http://derela.republika.pl/artillery.htm
410 75mm Inf-Gun - as infantry gun, an ordinary 75mm wz.02/26 field gun was used, so a weapon (7.5cm leIG) should be replaced with #64 75mm vz.02 FG (differing in longer range).
If it's important: ammo load in limber and caisson in infantry units were 80 shells (plus 36 shells in caisson's limber).
Icon should be changed to 2111 (as unit 412 - longer barrel)
Speed 1 is correct - it could be pulled by the crew.
Weapon 064 75mm vz.02 FG - correct name is wz02/26 FG
It could receive Sabot round with pen=7, range=60, like weapon #55 75mm vz.02 DFG (75mm gun in AT role).
Then, the gun can receive few Sabot rounds, although not necessarily.
Form. 338 Infantry Guns could be renamed to Infantry Gun Pl
Precisely, they should be given 6-horse limbers instead of wagons, but then the player could also choose inappropriate artillery tractors.
Maybe a limber could be doubled as a kind of wagon?
I'm attaching some proposed pictures of wz.02/26, for 32135 is hard to recognize. It could replace ugly 21172 - also for unit #412 below.
390 Fort - 7.5cm leIG should not be used in Poland at all.
Polish gun-armed fortifications were very rare, but probably first of all, original Russian 76mm wz.02 field guns were used there (without special mountings).
Weapon #32 7.5cm leIG could be therefore converted to
76mm wz.02 FG, with the same specs as #64 75mm vz.02 FG (wz02/26)
Otherwise, main armament of the fort should be just replaced with 064 75mm vz.02 FG (wz02/26).
411 100mm How - was used since 1/30 (now 1/35). Maybe we could use a full name Howitzer? (or Polish "haubica", in lower case).
Icon 2115 with a shorter barrel would be more appropriate IMO (2116 rather fits for #403 120mm gun)
412 75mm Howitzer - should be 75mm Field Gun or Canon (or Polish "armata") or 75mm wz02/26 FG.
In a limber and caisson, 96 shells were carried (plus 32 in a caisson's limber).
413 75mm Howitzer - same as above as for a name, but 75mm wz.1897 FG.
It should be used since 1930, being Polish most common field gun (now: only from 11/39).
Secondary weapon should be changed to Polish carbine 144 (even if it wasn't used in France - or we can create two units with different rifles to be precise).
In a limber and caisson, 96 shells were carried (plus 24 in a caisson's limber).
Icon should be 2112, as French OOB unit 28 (it had quite long barrel).
Better picture is 28018 or 23083 with wooden wheels - current one is French motorized version (same for unit #329 75mm FG Bty)
Weapon 033 75mm vz.97 FG - correct name is wz.1897.
Sabot range should be increased from 20 to 60, like weapon #55 75mm vz.02 DFG (75mm gun in AT role, shooting full AP shots).
414 75mm Field Gun [AT gun] - firstly, in Poland there were no 75mm field guns specifically assigned to AT role, they had no special sights (apart from a handful of guns) and there was little AP ammo available for them (20 per battery).
The same role could be fulfilled by 75mm Inf Gun or Howitzer above, with Sabot ammo, which would offer longer HE range (they would have to have less AP ammo - but it would expend its 8 AP rounds for first few targets anyway). In fact, 75 mm guns could destroy most tanks with HE in 1939.
If we decide to keep it as AT gun, it could be used since 1/30 (now: 1/35), and fill a gap before advent of 37mm ATG.
But then, wz.02/26 gun should be eventually replaced by much more numerous wz1897 FG (as above) - a name of weapon #55 75mm vz.02 DFG can be just changed without harm to other units using it (the river craft used wz.97 guns as well in fact).
In all 1939 guns, rifle should be replaced with shorter #144 carbine - it applies to units 399, 400, 403, 410, 411, 412, 414, 415, also to 405 wz.35 AT-Rifle
By the way: there was no weapon, like #221 wz.29 rifle at all. It should be eventually renamed to wz.98a Rifle (a modernized version of wz.98 Rifle), or changed in all units to #178 wz.98 Rifle.
391 Strongpoint - its weapon #55 75mm vz.02 DFG could be also exchanged to newly added 76mm wz.02 FG or 064 75mm wz.02/26 (like #390 Fort above). Such amount of AP rounds is wrong - it could be a handful at best.
416 120mm How Bty - it should receive fourth gun, and a proper name is 120mm Gun Bty.
Radio should be 91 (now 92) - it was very rare.
418 wz.25 AAMG [2] - it should be wz.14 (see remarks for 408 CKM wz.25 Pl).
Hotchkiss AAMGS were mainly used in stationary AA defence (along with wz.08 Maxims), but in infantry units a standard was
wz.30 HMG on convertible AA mount, which should be added as new weapon (it should be also an armament of #548 Taczanka).
420 13.2mm AAMG - there were few used, by the Navy, on stationery naval mounts, in coastal defence. To be removed IMO.
423 194mm Gun Bty - it must be French allied support, but more probable would be a support of ordinary 155mm GPF guns (unit 220 in French oob, with changed class).