They did not make Convertibles in 330 and 440 models, only Polara and Polara 500. Production numbers are hard to find but I have seen on the net are a total of 37,600 Polaras were built that year. No breakdown of convertibles. Polara 500 was considered its own model and a total of 7263 were built with 1634 being Convertibles which this is one. The 500 is mostly trim, a 500 badge on the fender for the convertible, or roof panel for hardtops, side trim going up to and through the door handle(regular Polara's are just below the door handle), a big chrome panel on rear quarter before the bumper, wheel opening moldings, etc. Then the 383 2 barrel motor (which this was) was standard with an option to a 4 barrel 383. Bucket seats were also standard. Probably more but all I can think of at this time.