Nearly pristine used UCAs at a pick'n pull. Really? Everyone in the rust belt hates your guts right now
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I just did my lower balljoints by swapping spindles, so I bought one of the UCA boot kits in case I mangled a boot separating the spindle.
The kits are cheap but FWIW I would go the grease injection route if possible, that is if you are sure you didn't tear the boot and the joint is still tight.