live2bowhunt,
I just checked my 2004 Liberty vs a 2003 Pro40 Dually to double check for you and I noticed last season what you did with the 2003's .......obviously so did BowTech.
They redesigned the risers on almost all the 2004's, slid the entire sight window over giving you a much wider field of view and on some sights you'll be able to see your entire sight aperture.
Tagging along with this benefit (Or the other way around) is the one you alluded to in your post.......by moving the sight window over and widening the arrow shelf, centershot on the 2004's now sits at the centerline of the grip. (My Liberty appears to be exactly in the center.
I would expect to see this on all the top end 2004's with maybe the exception of the Pro40 Wheely (On a 2003 riser) and the Ex_VFT. although I never owned either of these bows.