yes there is, but if you dont have an xbox or psn account (when that content was available) related to the pc version of your game, and you "casually" have all the DLC content when you go in your game, a message will pop up above the radar, thats says "welcome back blablabla", the DLC content its for returning players to the PC version. so if you dont have and account on xbox or psn related to your game, in that case its a ban, besides your SP save file will be corrupt, tested, 2-weeks banned on the first ban wave, had to start story mode all over again
thats memory editing, and root-game files editing, its like the cheat engine shit, 100% Ban
but it doesnt matter, even if you had the game when all that content went out, now rockstar its removing it on pc version, check the complains in rockstar support forums
if you want all that, just give yourself all the weapons each session, its easier and faster
but if you want the dlc content unlocker, its at gta-mods dot com (not allow to post links, search there)