To close out this thread for future reference, I couldn't see much on my stock '48 with the window installed so I decided to just cut the aftermarket guides to fit. If it ends up not being the right thing to do then I'll just buy new ones. I cutting them just above the second hole on the guide. This allowed the guide to sit in the joggled area on the door frame that looked like it was made for it. With the part trimmed so the guide could sit flush it allowed me to better determine the hole location. It was obvious that the remaining hole in the guide did not line up with the existing hole in the door frame. I marked the location on the guide and had to drill a new hole approx 3/8" below the existing hole. Once I did that the guide fit the door. We'll see if it all works once I get around to installing the glass, mechanism and felt strip.
