Re: Colt Frontier Scout
The P suffix guns were made from 1962 to 1970; your gun was one of the last, made in 1970.
I think that frame is Zamac, not aluminum alloy. To remove light rust, I suggest brass or copper wool (pot scrubbers) and oil. Some folks recommend 0000 steel wool and oil, but steel wool can scratch bluing. Value would depend on the extent of the rust; a guess would be around $250, allowing a premium for the Buntline model, more if it cleans up nicely.