lowering convertible top questions

Ah, ok. Slit should be deeper in the well.
But mine IS the factory top because it is date stamped on the inside. With month, day, 1964 and manufacturer name.
This car is better built compared to my 1968 and 69 cudas. Hard to believe they'd intentionally do this at the factory. But thanks for the possible explanation.

Any idea where the 24.5 or 26" bow height is measured from?

I had an original 65 that was the same way from the factory in 1970 .. it sucked, because it was otherwise perfect. Here is how I was told to measure bow height even if the top is not on you can use the cables to help finalize the location
bow height.jpg