P08 ID

[unspellable]

I have a Mauser mismatch. It has the byf code on the toggle link. On the chamber it has 42. I had been assuming it was the date, but since it's a mismatch it dawns on me it might be the 42 code. SO, is it a 1942 receiver or a 42 code receiver?

(I've posted this in the wrong category, moderator, feel free to move it to the right one.)