David, I would not be too concerned about letting the sand blaster do your sheetmetal. While the acid dip does a great job it has it's problems if the metal is not thoroughly rinsed of the acid. On the other hand the sand blasting can warp the metal if left on it too long. That, however is not a real problem with the heavy gauge metal of the AD trucks as it is with the more modern vehicles. If the blaster is 1) experienced and 2) understands the importance of prevention of warping, you should have no problems.
Many of us here on the Bolt have had ours blasted with good results.
Good luck!
