The Boys Uhlig must have heavily sourced the mechanics in the Zella-Mehlis area. From this example it appears that they sourced the craftsmen in Liege and then had the the Zella-Mehlis fellas to finish it to the customer's whims. The reason for the Liege sourcing may be that the firm may have been on the last knot of their financial rope. With a couple years of this 1921 Z-M proof date, I believe the concern went into receivership.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=297114883Note powder & shot charge along with the January 1921 proof date and 188 ledger number.
I assume the mechanic represented by the encircled AG to be Belgian?
Kind Regards,
Raimey
rse