I have not tried to research where the different actions came from, the barrels range from some with one or two proof marks to none at all. Kirkwood published that Schaefer got his actions from Germany.

The workmen that I know about were

W.R. Schaefer
R. F. Schaefer started 1870
E.C Schmidt , Iron worker and finisher
J.F. Werner
F.C. Doell started in 1872 left circa 1884, stockmaker
A.P. Kessel stockmaker, also made Lefever stocks dates unknown

Does not look like I will ever have the time to publish on Schaefer or other shotgun makers so I've not verified some of this.

MP Sadly Deceased as of 2/17/2014