According to the research that i've done on this, the front wheel cylinders are 1 1/2" bore. The wheel cylinders on the rears (both) should be 1 3/8" bore. If you happen to pull the wheels and drums off I would appreciate it if you would measure the bores on the front and rear wheel clyinders to confirm. Also, the master cylinder is no longer available from Bendix. There isn't even a rebuild kit available. BUT the bore is 1 3/4" according to Bendix AND the master for the M35A3 is still available. As far as I could find out the only difference is that the reservoir is remotely mounted in the engine compartment on the passenger side. Also, if you could measure the bore on the master cylinder and confirm that it is 1 3/4" and let me know I would appreciate it also.
I don't know about the master cylinders, but I have looked into the wheel cylinders.
The supplemental manual linked to above (smarpi 9-2320-209-14&p) on page 1-4 clearly indicates that the "brake hydraulic wheel cylinder" is not unique to a split brake A2 truck. It refers you back to the -209 series manuals for any operation, service, or parts information that is not unique to the split brakes. In TM 9-2320-209-20P on page 243 (with illustration on page 245) it calls out the following:
114 8 PAOZZ 2530-00-274-4511 7411010 19207 CYLINDER ASSEMBLY, HYDRAULIC BRAKE, WHEEL (SEE FIG 115) EA 6
All six have the same part number, also confirmed in the -361 series. It is very common to find essentially the same wheel cylinder with only the bore changed for various similar applications. I'm going to go out on a limb and say that if there are different sized wheel cylinders on an M35, including the A1/A2 variety that either intentionally or unintentionally someone has modified the truck from the original.
Just to throw out there, I have NOT looked into the A3 on this subject, and for this post I don't care to speculate about them, but it should be easy enough to look up to see if they match the above NSN or part number..