Was ist ever confirmed that it was in fact a laser? I wanted to make a trivia question out of this ProLok protection, because “lasers for copy protection” sounds just weird enough to potentially be a nonsense answer without context, but I couldn’t confirm that the holes were indeed made with lasers, and not with other means.

Good question. I don't know the answer, but I'm quite certain that it didn't really matter what mechanism was used to mark a diskette. Any damage would be equally strong as a way to detect copying.