Yes Mike, the serial number (21143) is stamped on the back of the magazine box and 43 on the sear and set-trigger kicker. According to Speed the number fit in the range 1908 of his BU marked list.

I'm confused about the difference between Suhl and Suhler=Waffenfabrik? Town and manufacturing Co.?
But I also wonder if this was Oberndorf made? But no BU marks?

The time frame is correct to my thinking, Pre-1910.

Thanks for your help in confirming my thoughts and filling in the gaps, and for new info. Is this the same Schlegelmilch that made the shotguns?
SDH