"I replaced the roof and no leaks since then"

I probably wouldn't consider them. I've learned the hard way you can't believe most people. They lie, and will tell you anything for their own cause. If they acknowledge a roof replacement, they know good and well there was (or may still) have water intrusion. I agree, it's an excuse to justify ceiling stains or soft spots. Unlike when purchasing a house, when they say, "new roof" ... which IS a selling factor for a house, it's a RED flag for an RV sale. To me, it sounds like they are attempting to sell the RV like they would a house, as if a "new roof" gives it a better selling value! RV are not houses.