Weapon changes?

[Solid Spartan]

What do people know about any changes to the game's weapons? I know the XM16E1 has been changed into an actual XM16E1, but that's about it. Can we actually aim the M63 this time? Is there maybe any mod system akin to MGS4 with accessories of the time, like the Colt 4x scope, MACV-SOG vertical foregrip, etc.?

Glad the game has real guns in it instead of those frankenguns that MGS5 and its expansions/spinoffs/whatever had.