I'm not sure how these engine have their fittings, but I take it there is an oil and water line as in most 80's turbos?

I think if it spins freely, with minimal/no shaft play, it shows that it had adequate cooling and lubrication despite the HG issue and didn't stress or significantly expanded/distort the metal/fins while in use.

Do you have another turbo engine to place it under boost and see if it holds the set psi without excessive lag, drop-offs or bleeds? If not the only way is to re-install and find out after the HG job.

I got my fingers crossed your head is still within spec, I gave my Mercedes a viking's funeral when I realized the head was warped after overheating it. I kept the revs at rev limited until it overheated and died a smoky and flammable death. In retrospect I probably should have tried that wizard-fluid mentioned above, since I was left walking for awhile until I found the Montero.