Yeah. In PnP there's a bunch of good oldies. But in 77 there's gonna be a bunch of new stuff, so it leaves a little room for contemporary models. However, as the guns in 77 seem to run on contemporary, smokeless powder, cased ammunition (the Colt AMT looking gun is labeled '50 AE- a holy grail of all gun nuts who never had to use that overkill nightmare in combat), so there isn't any logical reason for not having some AKs, ARs, Steyrs etc. Especially in modern form, that look cooler and more functional (and are more functional) than the usual over the top cyberpunkish/futuristic designs.
Generally, in reality. If a completely new gun is to be adopted by the US or Russia or China tomorrow, it's gonna be around until different propel system for the projectile is developed. Be it a binary liquid system or magnetic acceleration or a direct energy weapon (probably never gonna happen, KE beats DE on every level, except in space).
I'd really like some AK, ARs however, as I'm really dissapointed by the long gun design in 77 (small arms are great though - functional and not overthetop, yet with cyberpunk vibe), the smart gun (which is nothing like smart gun from PnP), the big tech gun - those design are among the worst in the cRPG history)
But I'm still hyped as fuck for the game. My V just won't use that junk.