Device found!
the threaded portion of the stop rod is 6" long, the knurled knob is 1 1/4" diameter
the spacers are 1" dia. and 1 3/4" long with a 13/16 through hole
the mounting stud is 3/8" dia. with 7/8" thread on one end and 1/2" on the other, the two thin nuts are 7/8" hex and 3/8 thick
the slotted bar is 1/2" thick X 1 5/16" wide with a 13/16" wide slot, milled 4 1/2" long, and 5 1/2" long.
The end of the stop had a 1/4" ball inserted into a shallow hole in the end, the end of the stop is rolled over to retain the ball and allow it to freely rotate.
Why I was initially unable to find the device was I was looking in the wrong place! Of course, it was intended for the lathe QCTP, but mostly it gets used as a vice stop on the mills; I have drilled and tapped holes in the sides of my mill vices on the area behind the fixed jaw to accommodate the stop.
After finishing all the parts, I niter blued them, using the US Armory method, in a heated (600-650 F.) mixture of sodium nitrate and potassium nitrate for about 5 min., then in a hot water bath to wash off the salt, then into hot quenching oil bath. This effectively prevents rusting.