Well, this isn't total concrete way to decipher the year and type of 6.0L, but the LQ4 motors came with 317 casting heads. The LQ9s came with 035 casting heads. The only other way to find out is to remove the head from the motor. You might want to do this anyway to go over and fully inspect and clean it before you go off and install it. If the head bolts are of varying sizes, then you have an 03 and older 6.0L. If the head bolts are of all the same size, then you have an 04 and newer. And when you do take the heads off, it is a sure-fire way to discover if it is an LQ4 or LQ9. The LQ9s have flat top pistons--and the LQ4s have dish top pistons.