Keep in mind, unless you are a dealer you are under no legal obligation to disclose the frame work unless you are asked directly about it.
Dealers are kept to higher standards.
If you position it right, you can turn it into a positive.
"Man, this thing was rusted to hell. I had it welded and treated. Should be good now."
"Jeep frames are notorious for rusting. I planned on keeping it forever, so I removed any signed of rust, did any work it needed, and coated it with POR. It's better now than any jeep off the factory floor.
That's all I am saying