There are multiple locations in GTA 5 where you can find RPG. We marked some of them on the map bellow and we have screenshots for each location as well as this weapon’s stats.
Available Weapon Upgrades
|Army ||Desert sand color||$100|
|Black ||Black color||Default|
|LSPD ||Metallic blue color||$600|
RPG Location Screenshots
Well I went to the altruist camp and it’s a assault shotgun lol