I found it on the
http://www.brianswayneonline.info/index.html
Swayne has the pictures of the non rear pump and the rear pump VB's and they are different.Check out the size, spacing difference of the passages around the spool valve area!!
I would bet the spool valve that goes with each is different. It is not shown... :~(
I will try to upload the picture. You can use that link and look around for the pictures is you like. well, another case of Al's internet paying off with info!! :~) Kevin, I'm just like you... didn't know that one!!