Caster Shims

I was looking at the caster adjustment on my 98 XJ and noticed that on the drivers side it is adjusted all the way back so there is no room for shims; however, on the passenger side it is adjusted approximately 1/4" forward but there are no shims in there. Is this normal? It appears that the only thing keeping everything in place is the control arm bolt.

You should have shims in there if it is 1/4" forward.