I downloaded GR the first day, even though I can't play it on my current system. I tore into the files just to get a feel for the game's structure.
1. There is a Mod file.
Just as train tracks suggest the occasional presence of trains, inclusion of a dedicated mod file in the game's file structure implies a tendency toward modability.
2. GR uses .qob files that appear to be backwards compatible with the current 3ds max plugins like RS but just a little different. It's a matter of scale. The muzzle flash is different and the point where the brass casings eject will have to be adjusted.
3. GR .rsb files are a different format from RS, however there is already a GR rsb<>bmp converter available.
4. Kit file structure appears pretty straight forward. The weapons ammunition performance characteristics also seem to be a part of the weapon file itself, so, no more ammo files. Apparently it's gonna be FMJ only.
4. Suicide has a point, the game play will be different. GR is meant to simulate infantry combat. However, my point is that Tac Mod is my favorite weapon mod and if I wanted anybody doing GR weapons mods it's these guys.