I suppose each of the lugers assembled by concerns other than DWM and Simson, large or small -could possibly be a "variation".
I have no problem with lumping them together as "lugers assembled for commercial sale"; without finding some records we won't know the number or names(well a some are known as mentioned above) of the builders or how many were produced.
Several of us are still assembling "mismatched" lugers today.
