I wouldnt bother. I pulled my 02 5.3 at 150k. Motor was mint!!! It prolly had another 100k in it. Like everyone else stated, do a timing chain.

 

one thing to be concerned about with trays. if they are worn it has been known to happen that the lifter spins in the tray.. this isnt that common but has happend. if your doing heads then do lifters

 

I say, when you pull your cam, thoroughly inspect the lobes for any damage. More than likely everything is fine and you can re-use the existing lifters, but if you see anything out the ordinary (pitted lobes or gouges) I would definitely go ahead and replace the lifters. You don't want damaged lifters eating up your new cam or worse.