(wet sand everythng that is getting painted).
FYI, "wet" sanding is not the only way, it's one option.
You can dry sand, either by hand, or machine, scotch brite, or use a liquid abrasive scrub.
As long as you dull the surface, your good to go.
I prefer 600 grit dry, on a 6" finish sander with a foam pad for most areas.
Kebo, as timswi said, good materials can cost a grand for a job like this. So, for 2 grand, I don't expect a show truck. He is going to cut something somewhere, if he plans on making money.
Todays paint is too hard to be able to get anything to adhere well to it. So, the old clean it, tape it, paint it, $600 paint jobs are not a good idea.
If you have delamination on the front fenders, and the paint is all original, then realistically the rest is about to go too. Painting over defective paint is never a good idea. So, he needs to make sure the rest of the clear is sound.
One easy way to test, is to lay on some quality automotive masking tape, (not the blue crap), rub it down real well, grab one end and pull it off as fast as you can. If the paint is about to go, it will come off with the tape. If that happens, your looking at removing all the effected finish.
This is time consuming, and expensive.
If just the fenders are bad, just repair them. Why paint the whole truck?