Ron, et al,
IMHO, I think that this magazine may have been renumbered at some point in it's life for the very reasons that Ron mentions, but at the same time, I think the renumbering is authentic... I recall that being arsenal refinished is also a frequent event in the life of Swiss Lugers... (They sure liked them pretty, even for military service), and the possibility that a magazine went through a rehab and was officially mated to this gun is not unlikely...
The stamping of the numbers seems to be in the correct font and size, but Pete would be in a better position to judge that... I also believe the price is rather high for a gun that is refinished, whether it occured under offical auspices or not...
Speaking only for myself... YMMV