[brummbaer]

About A-129 Mangusta.
units 503-504-505-907-908-909 Basic version entered service 10/90 (total 45).
Typical weapon configuration was the Attack Helo (unit 504) with 2 missile pods with 8 BGM-71D/E TOW 2 (weapon 175-176)or 6 AGM-114A Hellfire (weapon 178) plus 2 81mm Medusa rocket pods (weapon 185).
12.7mm gun pods for units 503-505 were available since 1/97, though I couldn't find a picture of such configurations, particularly with Stingers. Mistral missile was also implemented, but maybe this is just a duplication for the game.
I found no source about 51mm and 122mm rockets (units 907-908), but 70mm rockets instead yes (couldn't find in inventory).

A-129 EA-1 (units 506-507-508): don't know if this refers to the planned scout version, but this one was deleted from production in the 90s.
Same applies for A-129 EOA-3 unit 484.

New version is A-129 CBT, units 509-510, which entered service in 10/02 with 15 new helos and the older ones upgraded. This is the first version to mount fixed 12.7mm Gatling gun under chin, TOW 2B or Hellfire ATGM and 70 or 81mm rocket pods.

In the end:
units 503-505 unchanged, available 1/97-10/102;
unit 504 W1 8 TOW 2/2A or 6 Hellfire; W2 and W3 2x81mm Medusa, available 10/90-10/102; alternatively 4 Tow or 3 Hellfire in slots W1 and W2 and Medusa in slots W3 and W4;
unit 509 W1 12.7mm (weapon 180); W2 8 TOW 2B or 6 Hellfire; W3 and W4 2x81mm Medusa, available 10/102-12/120;
unit 510 W1 12.7mm (weapon 180); W2 4 TOW 2B or 3 Hellfire; W3 2x81mm Medusa; W4 4 FIM9 2A Stinger, available 10/102-12/120;
old and new version actually cohexisted for some time, but hard to determine how long.
units 484-506-507-508-907-908-909 to be deleted.
Sources: italian defence magazine and Googling "A-129 Mangusta".

Edit: forgotten 12.7mm gatling in slot Weapon 1 in units 509-510.