In case it adds to the conversation.. I ran out and did some measurements on my 1200lb rated 4x8 folder. Keep in mind it is probably over 15 years old and has seen a ton of use and abuse. So there may be some sagging due to age, as well as possible design changes over the years (though I'm not aware of any on the 1200lb one).
The top of the frame to the top of the factory fenders is almost exactly 2.5"
The outer edge of the fender is about 7.5" out from the frame. They overhang the widest portion of the tire sidewall by about an inch. Though this was a rough static measurement on only one side. There will be some side-side play in the spring mounting.
The side frame rails are slightly under 3.25". They are taller than the cross rails so they can nest in to bolt in place. The cross rails are a little over 2.75". I think the frame is a little different on the heavier duty version though.
Some changes I noticed over the years:
The original 1700lb rated trailer had stake pocket holes cut into the frame, a round tube axle, and a bit upgraded tongue bars/mounting. Higher rated tires, 5 lug hubs/wheels.
The 1200lb rated one had stake brackets that you bolted to the side, a square C-channel axle, and the rear tongue mounts were just welded on tabs basically. 4-lug hubs/wheels and lower rated tires.
It looks like the 1700lb rated one now has the same stake brackets, a square tube axle (doesn't appear to be C-channel). While maintaining the upgraded wheels/tires and tongue bars/mounting. I believe they used the same fenders and fender brackets across all versions/years. But they could have mounted higher up on the frame on some versions. A detail that would be hard to detect unless you had both right next to each other.
I actually purchased one of the original 1700lb kits, unassembled, from someone off craigslist. I ended up using the frame steel to build my current trailer project. I planned to use the rest of the parts to upgrade the 1200lb frame, but I have yet to get around to it.
