There should naturally exist more Raikou ex than the rest right? If we consider that you get one Raikou per box and 3/9 of the other ex (Source: Guide to early EX Series pull rates - #3 by zorloth ), there should be 3x as many Raikou coming from booster boxes as other ex in the set.
Obviously this number will fall due to blister packs and other products but I’d still expect twice as many Raikou. Anecdotally I see Raikou ex listings on eBay Aus roughly twice as much as others from the set as well.
It’s definitely interesting though. The condition seems to suggest some sort of binder storage over many years, aren’t the stolen dogs generally higher grades than these?
I guess we’ll never know unless someone comes forward if it’s a Raikou collector, some who mass opened boxes on release, or cards stolen from a factory.