Based on my close examination of a 1904 Navy Luger #36 which is shown hereunder, it happens to have a standard (9 mm) magazine which is numbered and matching to the pistol. There is no doubt that the magazine is absolutely correct. If my eye sight serves me well, the C/M proof mark on the magazine base COULD be on the left side of the dished base, but I could be wrong because I do not access to the actual photo which is in storage.
I hope this image and information clarifies somes points regarding this interesting discussion.
In regards to the M1902 Carbine with the C/M proof mark, it is not abnormal for a Luger carbine which is DESTINED to a Navy Department for the purpose of a (fencing) prize to be stamped with this proof mark. The proof mark could simply mean in this case 'destination' and not 'issue'. In order to make a reasonable conclusion of an item, consider its originality, provenance and consistency of its details.
Cheers,
Albert