Well indeed is was Express proofed. "Crown" over "U" is the stamp below that. Proofed as #846 in June 1925. There many be a marker's mark right up at the frame. Very nice example by the way and I would suspect the maker would want his stamp on it somewhere. If the breech block is stamped say "Syst. Aydt D.R. Pat." or "Original Syst. Aydt" and there is a serial number below that then Haenel made it. If there isn't a serial number either Haenel provided the frame or Haenel had enough work that they were churning out the frames and thru caution to the wind regarding serialization.
Kind Regards,
Raimey
rse
