Two is a good number!
I did read somewhere that it's not a good idea to use the older round steppers. Gosh, I wish I could remember where I saw that, but they cited a couple good reasons.
That's a pretty hefty size for 300 oz/in. Certainly that is powerful enough, but with a newer stepper you can get that same tq in a considerably smaller package.
That being said, I'm pretty sure there's no reason you couldn't use them. I wonder if the mounting flange is a standard NEMA 23?
Working for Toyota, I have to sadly see a lot of good "junk" head off to the dumpster, and there's nothing I can do.