I do not remember exactly but the reinforcement of the window van is lower, further apart, or is formed with a cutout.
In our case the reinforcement blocked the lower edge of the window by about an inch.. for that reason the locking clips on the bottom of the window do not fit.
As mentioned I did not want to alter the structural parts of the van because of the 4*4 use and also because our youngest was behind that window in a car seat. We drilled 1/4" holes in the reinforcement and used screws to pull the window close against the seal.. then put a bead of sikaflex around the whole window to get the best strength out of it.
Good luck
Johan