Jani, ellenbr the photos that you posted regarding the Sauer tubes without extentsion are for a LeFaucheux (sp)action which is from a completely different time period (much earlier and much different action)than Jani's illustrated gun. Here is what we do know for certain. No. Sauer Serial number. No cave man with stamp. If I had to "guess" as to what I am seeing here, it is that the Gun was/is a "lunch box special" made with parts smuggled out of the Sauer plant and finished in some out workers basement in Suhl. That guess is as far as I am willing to go as to what Jani's gun actually may be. Jeff S.