Questions about an earlier M1 Garand

[Joe W]

I would change the rear sight to the correct locking bar type

Lock bar would not be correct for that rifle. It would need the Flush nut.
As to the "SA65", that indicates that the rifle was inspected and overhauled at SA in 1965 but does not mean that the barrel was installed at that time. If the barrel was serviceable it would not have been removed. The barrel most likely is original to the build. The face of the chamber appears that it might be parkerized. If so, that would indicate that the barrel and receiver were refinished as a unit. Had the original barrel, or the barrel that was on the rifle at time of overhaul, been found to be unserviceable and removed, the receiver would have been refinished and THEN a new barrel installed. In that case the chamber would not have any parkerizing on it. As collectors say, it would be (in the white). Nice rifle. It appears that is how it left SA in 1965 and I would keep it as is. There is no point in putting ALOT of money into a restoration of a rifle that has the rebuild marking on the receiver leg and also these Government Arsenal rebuilds, that have not been messed with, are becoming collectable in there own right.