1915 Erfurt Artillery...?

Ok, so how about a "little" controversy ? Saw a luger site advertise a 1915 Erfurt Artillery...


The ad reads as :


" 1915 Date Erfurt Artillery. The only authenticated 1915 Artillery known and it is a complere Mint Matching Rig with Perfect Leather and all accessories including sight tool, cleaning rod, snail drum with loader and Dust Cover. Serial #6939 (see Imperial Lugers, page 92 by J. Still ) P.O.R. "


Does anyone know about this arty ? Is a 1915 Erfurt arty possible ?