Alot of those trucks are also supplying rebuild parts to the re-set shops in Qatar and Kuwait...They will take parts off them, rebuild them, and reinstall them on other trucks...Lets say a control arm for instance, it will get new bushings, ball joint, fresh coat of paint and its good to go back on another truck...Same with frames, engines, transmissions, and about everything else, except expendable parts...ITT is one of the biggest companies doing this and they pay good money...
Or work for customs in Germany like my friend did (german born american dual citizen courtesy of father in US army) and slowly amass parts through wheeling and dealing with the US Military...He almost has enough to build a complete HWWMV...