From what my Dad told me.
It’s almost impossible to find one from CMP or anywhere else an original WWII one with matching numbers. The GI’s would sit around, break down their rifles, and trigger assemblies, op rods , etc would go into a pile of helmet. One guy would clean all the triggers, one guy the rods, and of course someone or more got the barrels. When they were done ..... everyone just grabbed a trigger, Rod, barrel and threw it back on their gun. No one worried about serial numbers, when the next day you were going to use those guns against the Nips!