I didnt think they put air bags in the heavy duty trucks? But no, no ford diesels at all in the yard i went to. I did almost buy an airbag column because I like the look of the airbag wheel but wasnt sure if the wiring would be the same or not.
I did some reading on the CARS program (clunkers) and the yards can only part out the cars for 180 days then they must be crushed or shredded. the engines are all killed by draining the oil then filling with 2 quarts of sodium silicate and running them till they seize. there are also some "conditions" to selling the rest of the drivetrain, of which I havent been able to figure out.
the way the rebates worked were based on how much more fuel mileage the vehicle you were buying got over the clunker you were trading in. had to be a 10mpg improvement to get the full $4500. So if you traded in your old diesel for a new one you would probably get more for regular trade in value than under the clunkers rebate. I havent seen a diesel in any of the u pull it yards here, they usually go to the parts recyclers that pull the engines and such.