Richard,
You are essentially correct. 1900-1906 Lugers definitely have unmarked mag bases. Alphabet Commercials (four-digit/letter suffix) made between 1922-1929 are commonly accepted to have GERMANY stamped bases, but this may not be accurate and is something I would like to track down. It has been suggested that magazines so marked have come into this country as spares.
Since Commercial mags are by and large unmarked, it is almost impossible to determine whether or not any given magazine originates with any given gun in order to do any sort of correlative study.
1908/1914/20DWM (5-digit serial# guns) may have blank bases as well. There are 5-digit numbered magazines, it is suspected that these are associated with Police or Commercial/Military variations.
There is one exception. 1902-1906 Lugers in 9mm were stamped
Cal 9m/m lengthwise on the base.
Since I have your attention...I am assembling a database of early commercial (1900 through the end of the 5-digit series) Lugers, and would like to add yours to the list. Could you tell me full serial number (no xx, please); type (AE in your case?); proof marks (and which ones) or not; presence or absence of GERMANY export mark; caliber 9mm or .30; Loaded or Geladen on the extractor. If you prefer not to do this in public, please feel free to email me
dwightg@pacifier.com .
Hope the mag base info is useful, and thanks much for the gun data.
--Dwight