Ask the dealer if the hose that connects from the cg supply to your RV has been pressure tested to 120 psi.
An RV would really be tested to 120 psi? I don't believe it - no way, nohow. That's not even done in new home construction. The lower quality plumbing fixtures typically used in an RV wouldn't stand up to 120 psi. And some of the fixtures have hand-threaded fittings like the faucets. Imagine flushing your toilet with 120 psi. You and the toilet would be in orbit, hehe!!
Did you know the tires on our new trailer have been pre-tested for over 2,000 mile from from delivery from the plant in Indiana to our dealer on the west coast? Hafta to be very best quality then....
Of course your wimpy 1/2 ton truck can pull that humongous 5th wheel on the dealer's lot. After all, it does say "1/2 ton towable".
Many more honest sales pitches out there!