63 early build?

It depends on your VIN and which part you are talking about. 308x7S100001 to 308x7S121513 is the total range, where x=3 for coupe, x=6 for convertible.

For example, S104047 - end of Nov. S111833 - end of March

Also, you can check the body build date on the trim tag. For '63, these are "week" of the build, not the day. So A3 is the third week of September, not Sept. 3rd. 1964 and up us the "day".

Early in reference to the floor storage areas is up to Nov, I believe. Late for when Muncies began is around Feb, I think (could be wrong). Late for when AM-FM began is around March.

Late for the gas lid is a broad timeline. The switch began May around 15,000 but some July cars had the early style lid (Noland's survey is incomplete and wrong at 18,000 for an end). However, most cars by 17,000 - 18,000 did have the late style. If you have a '63 lid on yours, keep it or replace with the same style. The styles are roller or nylon slide. The roller is considered "early" and the slide is considered "late". The roller uses a nylon wheel on a spring clip with an exposed hinge and the slide uses a nylon plunger with a covered hinge.

Trim Parts does some of the nicest repro parts in the way of tail lights and such. Might be true on the lid also.