barrel saddles on roping trees?

At the auction the other night, I was asking one of the men there about this nice looking barrel saddle that was going to be sold that night and he told me it was on a roping tree. I know it wasn't a roping saddle, it said barrel queen or something like that on it somewhere, but I had never heard of these before. Are there actually barrel type saddles out there that you can still tie a rope to?
Thanks