Since they were both at least operational I would suggest rebuilding them....but that assessment will have to be made after you remove them. A cheap hone from the parts store will do fine unless there are deep pits that won't hone out. The little pits in the CENTER of the wheel cylinder will not hurt as the rubber cups never close that tight.
These are real simple and should be no problem for you. If you do not have a shop manual then you can access one here:
http://chevy.oldcarmanualproject.com/Good luck and let us know how you make out.
I will add that cylinders, as well as the kits, for your model year should be available through your local parts stores and not that expensive..... NAPA for sure. Then you can spend the otherwise shipping cost on some other goodies
A little homework can save a lot of moo-la.
