I stand corrected. VW and a few others are running direct injection gas motors...

I guarantee you their adjuster is figuring replacing the engine with a used one. The only problem with that is they are completely impossible to find. He probably called a couple of yards and priced out a Cummins, not bothering to mention it's a 2007 model. Up to 04.5 they are out there for about $4500, leaving $1500 for labor. Even if he did mention it was an 07' the guys at the yard probably just shot out a dollar amount assuming he'd never call back, and if he does it's high enough to find one.

What I'd do is get a hold of the adjuster and find out where he quoted the replacement engine from, give them a call and verify that they indeed have a 2007 model engine with less mileage than what your truck has on it (like kind and quality). I'd bet good money they can't find anything. I know this because I work for one of the largest salvage auto parts companies in the world and we couldn't find one after a seller told an adjuster he could. I personally called 3 different yards that supposedly had one and didn't.