The tender pictured is 1946 production, not real common. It looks like the coupler has a black weight on it, that is 1949 and newer, so someone changed it. The 1946 coupler has a thin shank and no weight. Look at the valve gear on the engine closely. 1946 engines have round head rivets, 1947 and newer used hex heads. I think I see the reverse unit sequencer lock lever sticking up from the boiler, that is correct for 1946 and 1947 engines. If you ever disassemble the engine there will be a date stamp inside the boiler shell. This is most likely a 1946, nice find.