So would you say that GTA V is a mod of the RAGE Engine? Or an entirely new game?
Or are games such as Max Payne, Grand Theft Auto, Red Dead Redemption, Midnight Club all "Mods" because they're using the same engine? No.
A mod is a modification of a GAME, ie R&L is a HL2 mod because it uses assets from HL2, if it was made using the source engine with custom animations and assets then it would be a game running on the Source engine such as HL2, Counter Strike, Day of Defeat.