I just found an older #19 mount and was curious of it's age. On the underside this is how it's labeled- 19 then A.R.M.S, W.B.MA., U.S.A. It does not have the newer style feet, the levers are beveled at the same angle as the weapon rails. On the top, there is a section that is milled out in the center with two mounting screw holes, it appears that it may be the same dimension as a compact Acog? These holes are elongated to allow fore and aft adjustment. It has the two holes on each end for the STANAG rings. The milling appears like it was done at the time of manufacture because the finish is uniform throughout and it is made of steel.
I appreciate any input on this.