http://www.klindustries.com/dinghies/watertender.html
I'm not sure if it has foam flotation or just relies on the air in between the double hull.
I used to have a sports yak as a kid and it was air. That was a while ago, though.
The web site does not give too many details on the construction or flotation materials. I think the weight would be a clue as to if it had foam in it . . . also, if it did . . . the sides would be very/very solid and not able to be pushed in, etc. So, give the sides and bottom a press here and there, and that will tell you if it is foam or air.