[Blas]

To my knowledge, each cars top and side curtains are custom fit at the factory. Adding a new hardtop, or replacing an old convertible top with the newer style top will most likely require some adjustments to the side curtains. Fitting the newer style convertible top on my older chassis will be one of my Summer projects this year.
I know the Lift-a-Dots are jigged into position on the fiberglass bodies (there was a photo of the jig as I recall from the SCOF people that visited the factory a few years back). Plus I also have made a template for a protective shield for the paint for when the tops are installed. It fits well on many of cars I have tested it on. Surely the windshield angles are standardized too. But I'm sure over time molds and jigs are replaced, and they probably have multiple body molds too. In noting that the side curtains and tonneau covers are numbered for each car, it stands to reason that they are fit to each chassis at the factory; Or why number them?
I have a new set of side curtains and a new style top for my older chassis. The fit-up with the windshield, while close, will require some adjustment. And the door ferrules are best described as "Tight" but they do line up. And I know the new style top requires 2 mounting Lift-a-Dot tabs to be replaced with different style connectors in the same locations. Keep in mind, I have an older chassis and the replacement top is from a newer style chassis. I'm sure the newer chassis are more uniform in shape than the older chassis were. We aren't talking about Impala's from a production line here. I have some other info on the hardtops to that I'll add here later today.