Y&Y has become one of my favorite spots over the past couple of years, as the food is above-average and its decor is simply outstanding.
I've spoken with much of the staff there about the theming and they all say that every statue, ornament, and piece of furniture you see in there is 100% authentic. There have a been a couple of times I've questioned that claim and attempted to poke around, trying to uncover some "Made in Lake Buena Vista!" sticker stuck on something, but I always fail and thus am pretty sure they're telling the truth -- there's simply no way you could recreate some of stuff they have in there.
This past trip I finally decided I'd grab some shots, and this turned out to be my favorite as I love the statue, stairway, and insane detail among the walls and ceiling. Naturally I did this after I had the Kobe burger, which I HIGHLY recommend. It's excellent -- just like everything in WDW.