No, you don't have to see it to know that it's not DVD9 quality. It's IMPOSSIBLE to say that it looks like it has double the amount of space available than it has right now. You can say that the quality is fantastic or looks almost like the original but the person selling this already threw his credibility out the window when he said it was uncompressed.

And no, if the guy put his transfer to dual layer, it would NOT be the same as it is now. It would most likely be a helluva lot closer to the actual laserdisc it was copied from. You have double the amount of space to work with. It's a pretty simple concept.