IF (big if) you find a bolt, odds are the headspace won't be too far off. Headspace has to be very excessive (more than most believe) before there is a safety problem. And even if it is a little sloppy, reloading using only neck sizing rather than FL will solve that problem. It's actually worse if you have negative headspace as in that case you will not be able to close the bolt on a round and the only solution is cutting the chamber a little deeper.

Nonetheless, it is a good idea to check the headspace with go-no go gauges before you fire it, if that's possible.