1992 LA 360 low oil pressure.

Ima thinking,that should have been caught during priming. Given your clues, it would seem pretty unusual for the cam bearings to be cooked tho.
But you know , on a lighter note, in order to have oil pressure at all; there has to be oil in the pan, and the pick-up installed,lol.
LOL....that would be true. Indeed they did put oil in, but priming I cannot vouch for. I wasn't there.