Are Action Replay codes to rebattle legendaries detectable?

[N]

Let's say I load my safe onto desmume, activate an action replay code there, encounter a legendary and then catch it. Will this legendary be in any way altered from a normal encounter?

I'm not quite sure how these codes work, but afaik they should just remove the trigger that marked these pokemon as caught and so there should be no difference...

[Guest]

It shouldn't really be any different as far as I'm aware. However I'd recommend making a copy of your save file, use the codes on that copy, and then dump the legendary to .pkm and add it to your untouched save using PKHeX. This is because the AR codes that let you rebattle legendaries really just reset some flags in the save file that have the effect of allowing you to fight those legendaries again, but they (often) have undesirable side effects.