Thanks to everyone and all the replies.
I've pretty well studied all there is on the FR website including the brochure, but no info on construction.
We picked up brochures from several manufactureres at a recent RV show and the only one that shows wall construction was Salem, which is wood with alum. siding.
FundFinder Xtra has a decal near the door that indicates Aluminum structre, I think it says ALUM-X or something. I've seen videos on YouTube of assembly at the factory.
I'm fairly certain the XLR Hyper lights by FR are aluminum framed, (fiberglass siding) but again, no info on forestriverinc.com
Keep in mind I've only been looking at the light weight toy haulers, and I'm very familiar with all the brands available in my area. It's just seems that most fiberglass siding rvs are alum. structure, and I wondered if anyone out there knew for sure.
I've not called the dealer yet, I spoke with a salesperson at the RV show from the dealer and the weren't real knowlegable.