Can I check if a Mew is still inside a PokeBall Plus?
I am planning to buy a used PokeBall Plus.
The seller says that they don't know anything about the Mew.
To my understanding, the only way to check is to just try to do the mystery gift and claim it, but I shouldn't do it before buying, and prefer to keep it unclaimed regardless.
My question is, is there a way to check? I've heard something about a purple light if it's still there, but I can't find anything about it now.
Thanks.