Jan,
Firstly I must state how honored I was to receive your comments concerning my unit marked Lugers which I consider to be among the most interesting as far as history is concerned.
I have four of your books and my interpretation of the marks on the 1911 Erfurt was based on your book on Imperial Lugers, my favorite.I may have misunderstood the "script" for the R which you will see attached, which I interpreted as "R for reserve.
A close up view of the gun follows and you will see it is in very nice condition
The plaque in the case simply says Parabellum,
Erfurt, 1911 but I do not know its origin. It looks to be around the turn of the 19th century by the type of screws and construction but there is no maker's name.
Many thanks for your interest guys; I have a number of other unit marked Lugers which I will post if you are interested.
Kind wishes,
Murray