I got two copies from two different people on here last year, and I'm 99% sure one of them was Lee. They both included the same copy of the rear brackets, and I just used that to make mine. It worked very well, but the actual shape really doesn't matter...pretty much anything that imcorporates the original holes and locates the new holes in the proper location will work. Its the hole location that matters, not the shape of the bracket so much.
A couple of things: First, I can't remember if I ever asked anyone else, but has anyone else who installed a Cat skid made up reinforcement plates for the front mounts? Because the original skid was in a place with 2 layers of aluminum, and the new holes fall where there is only 1 layer, I used a sheet of aluminum to make up reinforcement plates that rivet in and create a second layer for the front mount. I just used 1/8" sheel aluminum.
Next, for anyone doing this conversion, be VERY careful when clearancing the bottom of the heat exchangers! Be patient and use a round file, NOT anything powered to do this! If you do use something powered, make sure its not very agressive. In my impatience, and my need for using power tools for everything (being dumb), I used an air die grinder with a carbide burr bit. It jumped around a bit on the aluminum, and it caught once and punctured the exchanger! I checked prices and availability, and trust me, you DON'T want to replace one! I repaired mine with JB Weld, which sounds butch, but its waterproof and has held for around 1000 miles so far. I check it often to make sure it doesn't leak, and so far so good. I just want to make sure nobody else makes my mistake.
Jim