That varies dramatically -- even in the far more normally discussed realms of legit (as in caught/bred/raised all via normal play), legal (could have been done by normal play, just entered via numbers in a spreadsheet instead. Might be super rare or represent thousands of hours) and illegal (could never have happened via normal play) pokemon we can't come to a conclusion. That is also befor
It would also depend what access to the hidden RNG value gives you. If it is something boring like finding hidden ID so you hatch shiny pokemon then most would say whatever, if you get some idea of the actual chance of success of a move beyond hat you might know as a good player then different matter entirely.