s/42 1937 Question

[ugafx4]

Ran into a pistol at a local gun shop. Would like an opinion on it.

I find the barrel rather interesting and the plastic bottom magazine that has been stamped with the serial really interesting. When I was looking at it in person both of these things jumped out at me. Hopefully someone can clear up what is going on here.

The magazine did have an fxo stamp.

I can provide more pictures if necessary.

Thanks!