I put it in my computer DVD drive and it played as movie in Media Player. It had a short intro/logo scene and then went to a DVD menu that said "Play Movie" and "Extras." As for how it runs in a PS2, I'll have to test that out when I get home.
Regarding the part numberings, of all the Demos I've added over the past two days, I can say that not all of them have the SCUS prefix. For example, the Shadow of Rome is SLUS-29139. Of all the "longbox" sleeved games I have, it is the only one with SLUS. Most of the small, square shaped, sleeved demos use the SLUS prefix.
Interesting find about the price... I never bothered to research any of them other than photos. Being unreliable, I took most of the photos myself rather than spend hours researching for ones already online. EDIT: I can't find where it sold for $70 on Ebay. Last one I see sold for $1.