From what you are being told yes but they may only be refering to the painted surface. Anything further east than manitoba I would make a point of crawling underneath and check out every bracket, cross member, frame rail, hitch component and bolt. Some surface rust from where paint chipped away is fine, but I'd hazard a bet you'd find a lot more. If you don't then that a fairly good deal although nothing extraordinary. I'd still pay the $150 to have a Dodge dealership inspect it but I have never had good luck with Dodges in the past so maybe I am overly cautious.
I've never been one to believe in the blue book value for vehicles especially in our market because very rarely have I seen it accurately reflect what the vehicle is worth or is selling for.
Also, my 2005 and 2014 F-150 fit 34" tires no problem with a 2" level. I say screw the lift and just level what ever you get. It could be done for under $200 (including the alignment) and looks way better IMO. You also say that road noise isn't an issue as you will not spend all your time on the highway but a few trips with loud tires will definitely change your mind. Talk to Bob over at Urban X and he will help you out when the time comes. My vote goes to the BFG AT2 tires. Running them on my 2014 and really impressed with them so far.