Terry, thanks for the effort and to whomever the initials "M.Sch." belong, he was quite busy post WWI up until the mid 1930s. 15k examples over 10 years at first sounds a bit much for production during the difficult post WWI period, but I guess it is possible. For now I don't think Schüler made it but it is possible he could have been the wholesaler who sourced the components and sub-ed the work. S,D&G's name and business was diced up and sold during this period and I'd continue to look toward Sloan's Sporting Goods and Adamy for the sourcing & work.

Kind Regards,

Raimey
rse