Type 2 Mauser magazine
 

Were any Mauser magazines stamped on the aluminum bottom with S/42, in addition to the serial, and eagle insp stamp??

No.

But armorer's spare magazines were S/42 marked.

Did they also have the eagle stamp and serial number? Thanks.

The number was added when needed.

And I will assume DE63 was added as well. Thanks for the info!

There were several varieties of S/42 replacements magazines. Here is a S/42 with SE/63. Other varieties are: S/42 DE/63, S/42 DE/154. These came without a serial number but might have had one added later to match a gun.

Thanks!!!

The "S/42" was a concealment code for Mauser manufactured products, and used on armorer's replacement magazines and parts.

The SE/63 was an inspection acceptance mark indicating that a government inspector confirmed that the item met contract specifications and requirements at the time the government acquired it from Mauser.

A particularly correct armorer would have the dies and take the time to number the replacement magazine to the firearm. Many did not.