If the player character in question is doing stuff the glowies don't want to be associated with having a rifle with $13,000 dollars worth of shit on it is the last kind of gun they should be using.
For plausible deniability purposes I think some of the guns should be like picrel, at least when starting out, something that isn't out of the realm of possibility for some guy who DOESN'T have connections to the government to get his hands on *wink wink nudge nudge.*
You should still allow players to pimp out their guns however they feel with all the retarded tactical shit, but the default version's should generally be stuff that fell off a truck you can imagine someone buying from a shady black market dealer. Maybe you could make that how the player gets exotic shit like the Scar with the grenade launcher, a black market dealer that "doesn't" work with "government" agents to get them more fancy and capable firearms that would otherwise be unattainable.