The tank used to have (it may still) a spurious RN painted on it: 3067668. This is a Lima M4A1 RN so that can't be the correct one. However, it also has another RN cut into the armor on the left side: RN 3033584-S.
This is in a range that is attributed to ALCO. It probably was built July 1943. It has characteristics of what is apparently a "late" ALCO production hull. These are a one piece glacis with a small bow gun casting and un-beveled side plate armor top edges. All of the late ALCO tanks were most likely produced with the late low bustle turret without the pistol port. This type has been observed in wartime photos with all three final drive assembly types, however this one was built before the one piece cut in. It also has its original idler wheels and does not have the travel lock installed. So judging from the pictures, it seems to have been brought back in pretty much original condition.
These can usually be distinguished in photos fairly easily by inspecting the bow gun casting area.