Please talk to me about this mag

[Eugen]

When I recently purchased my 1939 Luger with military stampings, it came with two mags.

I need help understanding this one mag. I referenced a few books I recently purchased but did not obtain all the information I had hoped. The mag is either bare steel or nickeled. I can't tell the difference. From my limited understanding and research it appears to be an older style mag with the round spring. The casing has no stampings or proof marks. I hope I am using the proper terms here.

Is the script stamp an "L" or "e"?

I understand the "+" is a spare mag.

What does the small stick looking eagle mean? If you can't see it from the photo it appears to look like a Christian cross with three stick feathers on two drooping wings. Below it is a "154" stamping. A Eugen Bender book I have has a photo of one very similar bottom except for the serial number, but the only info listed suggests that it is a Mauser inspection mark from 1934 to 1940. Does this sound right?

Any other comments on this mag would be most appreciated. Thank you.