Since you asked, I asked the sales manager to look at the hour meter for me. He reported that it showed just under 10K. Doesn't quite match the miles unless the truck averaged 75-mph... The owner who traded the truck reported the miles as being accurate. If I were trading a high-mile truck, I wouldn't report more miles than what the truck actually had...
Is it possible hour meters aren't always accurate? Could some prior service (ECM, or other electrical component) produce this result? I don't know. I do know that the instrument cluster records and stores the mileage, and that mileage is kept even after the cluster has been out of a vehicle for long periods. The used instrument cluster I installed in Lil Red showed 1931 miles when first powered up. Clusters can be reprogrammed at dealerships, but this procedure is carefully monitored by law. I had planned to have the dealership zero-out Lil Red's cluster, but it would have been a big deal and required more paperwork. I decided it wasn't worth the hassle.
I reported what facts/photos/GM data were available to me, you decide.
Jim