Nice. From what I've learned they should have the black plastic mag. They stopped numbered mags in 1941 right around the time they went to these mags as they can't be numbered.
Thanks guys for all the replies. I was thinking the Mag was probably never numbered. I would like to find a Black Grip Luger (Black Widow Ha Ha) BYF 41 or 42 as well at a reasonable price.
I agree that aluminum bottom mags ceased being numbered in later 1941. The comment above says the u block and I believe it was in the w block but that is only 1-2 months apart so not worth arguing over. I also agree that Mauser did not number black bottom mags but that when used on the Ku assembly by the LW they were etched or panographed on the bottoms for those specific Lugers by the LW assembly facility.
There is no question that large numbers of aluminum bottom mags continued to be factory matted to Lugers throughout post w block 1941 production and basically throughout byf 42 production. These were fxo aluminum bottom mags with no number and no acceptance stamp on the bottom as it was on the body. I have no idea if there was any correlation between what type of mag was factory matted with a Luger and it’s grip type or even if it was possible that mags of each bottom material could have come with a single Luger.
I find it very interesting that the German police would not accept composition grips or magazine bottoms on their Lugers. The use of the materials was not decided by Mauser but by the OKH ordnance office (on behalf of the OKW and the services) and worked out with Mauser as the provider.