Factions should be able to bring in specific guns, relevant to their faction. it's not like the streets are flooding with guns, it would be nice to have easy access to only specifically the guns your faction would use. Overall making for a better more immersive roleplay. If the problem is minge players getting more ways to get guns, its's not like it's that hard to get into one of the few factions that do have gun rackets.
Some examples could be
Polish getting Slavic guns like the scorpion or AKM
Jewish Facs getting Uzis or The IMI Galil
Italians getting barettas
The vet/biker gang getting Colt 1911s
There's some Asian specific guns too I can't remember, but nonetheless, Cops harass (exaggerating) people for their firearms license enough to keep the bad ones in check at least enough.
This doesn't mean a price change either, personally, I think things flow pretty smoothly, from a user standpoint, as far as money movement goes.