Yep, the Clay Bar treatment is GREAT for getting the imbedded scud out of your paint!. I recently did it to my 'new' 09 before applying good coat of NXT 2.0.
There was very little 'grime' in the 09's paint,,,, (you can tell by how 'dirty' the clay gets) There was only a little bit on the top of the cab and on the hood,,, didn't pick up much of anything on the fenders/doors/tailgate.
I clay barred a 8 yr old truck with good paint, and it REALLY REALLY did wonders to the SHINE!!!!
If your paint is in good shape, an easy way to tell if your truck (car) can benefit from a clay bar treatment is to run your hand across a freshly washed hood,,, If ya feel any little tiny microscopic 'specs', it's time for the bar!!!!
The bar will not work miracles, meaning, if your paint is badly oxidized or just plain 'shot', the bar will not make it look new again.
Another thing to keep in mind...
The clay bar doesn't add anything to your paint,,, it actually can take a very very small amount of clearcoat off, so using the clay bar treatment too often is unnecessary, and may be detrimental.
Cay bar it only 'when it needs it', and just keep a good coat of wax (or paint sealer) on your truck... Enjoy!