[Suhiir]

Weapon# 122 40mm M203 GL HE Kill = 3
Weapon# 124 40mm M203 GL(3) HE Kill = 6

Unit# 172 AH-1Z Viper Hellfire x 8 APKWS II HE=19 AP=0
Unit# 173 AH-1Z Viper Hellfire x 4 APKWS II HE=13 AP=0 x2
Unit# 192 AH-1Z Viper Hellfire x 16 APKWS II HE=19 AP=0
Unit# 500 AH-1Z Viper Hellfire x 0 APKWS II HE=19 AP=7 x2

Units 172, 173, and 192 have Hellfire missiles, not much reason to carry HEAT rockets (which have much less range, accuracy, and lethality).

Unit 500 carries no Hellfires thus it has HE and AP (HEAT) rockets.

Keep in mind that while the US Army and USMC use much of the same equipment there are often vast differences in the numbers available and how they are used (for instance at the moment there is one tank battalion in the entire USMC ... 3 active + 1 reserve division) and there are things each uses the other doesn't (M113's and Bradleys vs AAV's).
They are separate OOBs because of these, and organizational, differences. So don't expect them to be quite the same.