For a house this age, we carry both 10-ball sealed-bearing nylon rollers and steel rollers, because what we pull out of a 1975 track isn't always what the door was built with - plenty of these doors have had one prior roller swap already, done with whatever was on hand at the time. We also carry roller brackets and short sections of standard track, since track wear on original hardware this old is common enough that we don't want to make a second trip for it.
We stock the hardware that fits mild-climate wear: rollers rated for steady use rather than for ice, since that's the failure mode we actually see out here. We don't carry every spring size or every opener board on the truck - that's a separate call if the roller job turns up a spring that's also shot.
One limitation worth saying plainly: if the track itself is bent badly enough that new rollers won't ride straight in it, we're not going to sell you rollers you don't need. That's a track repair or replacement conversation, not a roller one, and we'll tell you which it is before we start.