With you saying that it has a tang saftey,dose not sound like the first rugers.The first rugers had the saftey right behind the bolt,not to the side.I would guess that it is a Mauser that has been sportirized.
On a safe side have it checked by a gun smith.

As for the .308 it is a great deer round,the 150 gr power points should be just perfect for deer.
BBJ