[Weasel]

Here is one link I found. Click on the 1946-1999 tab at upper left and then scroll down to 1961-1974. Although the units listed are only by name and number at least we know which units fought in which battles.

http://orbat.com/site/history/

More links to NVA OOB and TO&E

http://www.gruntonline.com/NVAandVC/vc_nva_oob.htm

http://www.gruntonline.com/TheWar/forces.htm

http://www.gruntonline.com/NVAandVC/nva_forces.htm

http://www.gruntonline.com/NVAandVC/nva_vc_offense.htm (NVA offensive tactics)

http://www.gruntonline.com/NVAandVC/vc_nva_def.htm (NVA defensive tactics)