In my personal opinion, I think a better suggestion would be adding an Ammu Nation marker in Criminal Villa. Cops already have one in LSPD so I think it would be balanced, there's no problems with that..
You are mixing up Law Farm with LSPD. Criminals have Criminal Villa with spawners, without armor. Cops have Law Farm with spawners, without armor. LSPD is a feature that cops in real life have and it should stay as it is.