Jon, the other supplier of the "D" spoke wheel was Appliance. It was almost identical to the American TTD except for two areas: the machined lip as you have shown, and the lug nut washer recess. The Appliance wheels were machined deeper than the Americans. Both of these wheels were only manufactured in two sizes: 15 x 6 and 15 x 7, no 8" D-spokes were made in aluminum originally. Excluding the one wheel shown above I have only seen one other 8-1/2" TTD in magnesium. The American wheels have a backspacing of 3-3/4" for both widths, and the Appliance 6" wheels have a 3-5/8" backspacing whereas the 7" wheels are the same as the Americans...............................RatPack...............
***I corrected my measurements as I had posted front side measurements instead of the backspacing. Thanks to a member on here for pointing that out.