i read somewhere that rifleman upgrades will work on officers' squads.
does that mean that con bulletins work on the crews and not the gun itself?
If I recall correctly I believe I read that bulletins apply to the models regardless of if you use them to recrew a weapon or use Merge to put them in a new squad (I.E. if you merge them with Guards then then those models retrain the bulletin bonuses). The gun itself does not have the bonuses ( the maxim itself won't have the accuracy bonus).
If your talking about Weapon Crews on a default Maxim squad - I don't think so (I believe they have a different model in the game files for "Weapon Crew"). I'm sure its covered in the "Cruzz, the more you know" thread.