I thought I got lucky, welded towards the rear of the trailer was that document holder you mentioned. Inside was another plastic tube that was empty (dohh). I did find this metal tag, just forward of the Axle that looks like it does have a 17 digit number along the bottom. My guess is that is the VIN. It just has so much corrosion on the tag, you just can't make it out (also not much room to fully crawl under). I did gently go at it with a brass head brush, but I don't want to mess with it too much and wear anything away, so will just let the new owner sort it. My hunch is the VIN is also labeled somewhere else, but it's hiding from me. The good news is I looked over the frame and bottom with a microscope, and everything looks really well kept. Underneath Fiberglass is perfect, and frame and hard gas line is straight and in nice shape. The Axle is bolted on, unlike the welded on Axle of our Scamp
, not sure if that means it has been replaced or not. Well, it got at least one bid, so it looks like it's off to a new home either way. Thanks much again for the info, I'll know what to look for now if I ever come across another one of these.