Old Parkers were soft soldered. At least one damascus gun I've re-layed the ribs on was.

M21's seem to be soft soldered based on a sample of one, when Bruce took his dad's 21 to Andy longname's shop and they re-layed it on Shotgun Journal. Fox, Ithaca, LC's, Lefever, I've handled or disassembled ribs on were soft soldered.