Nothing is absolutely set in stone. We don't enforce the use of certain kinds of weapons or vehicles. The only rules are 1) No jets unless you are the US, Spain or China (and even those are very early in development) 2) No advanced optics, radar, ect. 3) No missiles.

Vehicles should be somewhere in the range of 40's to 70's tech, give or take, but without any of the more advanced optics or computer systems that vehicles started to use later on. Guns can follow a similar range but you may get a little more elbow-room there since firearms don't usually use any crazy computer tech. So any kind of gun that is 60's.. maybe 70's tech is probably fine as long as it doesn't have crazy optics and whatnot.

I think the Spanish have night-vision goggles and the like, so they exist, but they are probably not available to everyone. The same goes for a lot of tech, both civilian and military. If it's do-able and it makes sense, you can get away with saying it exists, but it shouldn't be common.

40's - 50's tech makes sense for Italy, since they were an isolationist dictatorship until recently.