Most likely no in this case. Theresia isn't a "known" title (unlike Resident Evil Deadly Silence, where most of the eBay copies are bootlegs) and while Aksys (not Atlus, as at least one seller has it listed) did a small run of the game, it's entirely possible that some stores that ordered it never sold more than one or two copies since they initially got it. The guy I bought mine from seems to have picked his up at some closeout sale (meaning I probably paid a few bucks more than he did, but I'm OK with that).
Nevertheless, I'd ask the seller if you're unsure. There are a few Hong Kong sellers that deal in nothing but bootlegs (box, cart, manual all wrapped up like new) and I'm surprised ebay hasn't yanked them off the site (well, they are paying their fees on time). Of course, most of these guys have 100% feedback and repeat buyers in the US, but when I see a game that's just come out for $12 plus a reasonable shipping charge, I'm going to be suspicious. Theresia is an older, out of production game with no big reviews or hype, so the price dropping from US sellers looking to get rid of old stock makes sense.
g.
Anyway, If you're still unsure after asking the seller, I can post a pic of my copy when it arrives