Yes there was a period when the half-ton had two mounting bolts for the core support and the 3/4-ton had only one. This oddity was much like the one about the core support cross braces where the 1/2-ton had them first and the 3/4-ton didn't. Also the three point vs. four point mounting of the cab entered into these changes because of twisting of the frame cab and front clip. I believe there were service bulletins out for some of these changes also if someone cares to check them out.
We had a rather lengthy discussion about this a couple of years ago and Woody may remember them, I've never had any luck with the search engine here.
Denny Graham
Sandwich, IL


Denny G
Sandwich, IL