Seized OEM calipers - refurb or core trade?

4runner: 2016 TEP trim (16mm caliper version).

I'm in the rust belt and a few years ago I replaced front calipers due to seizing. I still have the old (seized) calipers in the basement. Current brakes are still fine but I'm wondering if I should have my old (original, OEM, 16mm version) set refurbished, or just hold on to them for a core exchange (aftermarket/rebuilts) next time I need them. Planning full front/rear brakes service DYI in a few weeks so having spare calipers just in case might be the plan.

Aside, any recommentations for a caliper refurb/rebuild service in Toronto.