My van is a 2003 model it is very plain base model with the square head lights.
I was thinking of swapping to a newer front clip with the cat eye headlights and grill.
Does a newer front clip fit the older base models.
or do the front fenders have to be changed out as well.

 

The front clip does not need to be changed out. You are wanting the different headlights and grill.

You can “bolt on” these parts with one problem to be overcome: The headlight mounting brackets attach to the radiator support differently. In fact, the radiator support is a different part number for the flush headlights.

There are some articles and videos of how to modify (cut) the radiator support to accept the flush headlight brackets.

After considering it for my work van, I decided I liked the ‘mean’ look of the single sealed beam lights.