here's what I gleened from my master parts catalog..
for model year 51'
rear wheel cylinders
Utility 1st type, 51-52
rear-front 1.5in diamater with 4 tapped holes
rear-rear 1.5 in diamater with 5 tapped holes
All-one-ton comercial (what my 2 speed has) 46-52
a single 1 3/8 in diamater wheel cylinder for each wheel. casting number 5450072
I couldn't find this part in the Wagner catalog my parts guy has, but I found the 3/4 ton listed had the same casting number but a different part number (not sure why)
there is also a 1.5 inch diamater listed for all utility 36-50 casting number 5300892
so if you can get the diamater of the wheel cylinder and the number of screw holes to mount it, maybe we can figure out what it is supposed to go too, or maybe it's just plain wrong for any stovebolt application.
hope this helps...
I'm gonna go pick up what might be the right ones tommorrow (hopefully) and if they are, I'll get teh part number for you too.