I think this example give some insight as both tubes were sourced in the rough and then finished by Sauer denoted by the Imperial Eagle and Barbarian(Caveman with a staff). Neither of the tubes were made at the Sauer plant. Then there are 2 quality stamps of a caveman with a club(unless he had to fit the tube twice) as well as the crowns and a sequence of Imperial Eagle, Caveman with a club and crowned S&S(Sauer & Sohn early mark).

By the way, Mr. Emery's example appears to have the Piper chamber/stepdown:


Kind Regards,

Raimey
rse