Remember you're betting your life on the brakes every time you step on the pedal. I'd reccomend replacing the wheel cylinders as a matter of cheap insurance rather than trying to rebuild them, especially if you can find original-equipment items, not imported ones. Old wheel cylinders have a chronic problem with rust pitting, and just replacing the rubber parts won't solve a leak on occasion. Ditto on the axle seals - - - -it's a reelatively simple procedure to pull the rear end cover, remove the axles, and replace the axle seals- - -low cost insurance you don't spoil the new brakes with rear end lube leaks. Do it once, do it right, and drive on!
Jerry
If one hones the wheel cyls and they cleanup with no pits they are just as good as new ones, mind you new wheel cyls are relatively inexpensive except when when you get into the larger sizes like 1/4'" and up, if they are pitted replace them.
if you are paying a shop $75.-$100.00 an hr to work on your brakes you automatically replace them-economics
ron
