I have a J P Sauer & Son sidelock which has the Sauer name on one sideplate, & Von Lengerke & Detmold on the other plate. It has the Knock About on the rib or top of bbl, forget for sure which. It also has Krupp bbls & 2 3/4" chambers, marked 70 on the extractor face. This one has double underbolts & a Doll's Head, Deeley forend fastener. SN by the DGJ article dates it to ca 1900.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra