The above pic of the tubes carries the "CHRK"(?) monogram, maybe with or without the "H" and the imprint can also be seen on the rib where it is also found, where it looks to be worked off. May the Klett's forged the cast tube as well as the lower rib and Sauer finished them. I don't think it to be a Belgian monogarm like the "Sl" on the pattern welded tubes. Maybe the "M" on the pattern welded tube is for mechanic?????

Kind Regards,

Raimey
rse