Won't they take the," It's an off-road vehicle, he off-roads, so not our fault." way out? I'll see about this.
Honestly, I couldn't say one way or the other whether they will go that route or not. I know that isn't the answer you want to hear lol, but im a firm believer in if you're going to give an opinion, make sure it's at least an honest and well thought out one.
First, do you have any modifications such as larger wheels and/or tires that could possibly throw the reading of the odometer off? Not that it would cause your odometer to break but I could see them using that route to say they don't believe the idea that the mileage is close to what it is stating now as correct.
Second, it's largely going to be dependent on the particular dealer you deal with. Do you have more then one dealer local to you? If so, I would recommend calling one of them first, then the other before heading up there to see what they say. That might help you narrow down which would be better to go to or opinions from a few different sources.
Many times if you go get work done at one dealer or have them diagnose something at the dealer, it is going to go in the system. Which could make it difficult to leave said dealer and then head to another one for them to perform something different if in fact were discussing warranty work or something of that nature. Might be overkill but I would rather err on the side of caution with this as I could see it getting kind of expensive or somewhat of a hassle rather quickly.
Again it would be a good idea to contact your insurance agent and get their take on the whole thing as well, especially if you have a good relationship with them. I know for me, I have an actual personal relationship with my agent so I can simply pick up the phone and call or text her cell phone for help or advice. I realize not everyone is going to have this luxury, but even if you don't have that level of connection with them, it would be wise to ask them. It could give you some bargaining chips or information for when you speak/visit with a dealer; if anything just to help ease your mind about the whole thing.
Keep us updated and feel free to ask away if you have any other questions or concerns.