There are 3 driveshafts used in 1963 & 1964 Cadillacs.
Since the Hydramatic transmission was longer than the “new for 1964” Turbo Hydramatic transmission, the front section is shorter than the ones used on TH equipped cars. This basically means that all regular body style 1963 Cadillacs, and the "62 series" 1964's came with the driveshaft pictured at the bottom of the above picture with the orange tape.
The 1964's with the Turbo Hydramatic (DeVilles, Eldo's & Fleetwood 60 Specials) had a longer front driveshaft section due to the shorter transmission. This driveshaft is the one in the center of the picture above.
The 1963 & 1964 driveshaft for the longer 75 series and commercial chassis cars was not only different in that they used standard Universal joints on the front and rear sections, and of course were longer, but the center members bearing support was taller. The driveshaft at the top of the picture is the one you will find in the 1963 & 1964 75 series/Commercial Chassis cars.
Note: the 1965 75 had an even longer front drive shaft section due to the use of the new Turbo Hydramatic which is a shorter transmission than the Hydramatic used in the 1964 75 series body styles.
Pictured below is a 1965 75 series front section (top) and 1964 75 series front section (bottom).
The 1964 75 series front section is approx. 45 1/8" tip to tip, while the 1965 75 series front section is 2" longer at approx. 47 1/8" tip to tip.
Center Member Bearing Assembly and Support Bracket
The 1963 and 1964 center member bearing & support bracket on 62 series, DeVilles, and 60 Special, and Eldo, is considerably different from the 1963 and 1964 75 series and commercial chassis in that the bracket assembly is shorter. The center member assembly used on the 1963 and 1964 75 series and CC cars, is the same as the 1959 to 1962 center member bracket assembly.
Here is a quick breakdown from the master parts book.
--> 1963-1964 center member bearing except 75 series & CC: Group 5.600 part # 567 6991
-->1959-1962 (all), 1963-1964 75 series and CC, 1965 75 series : Group 5.600 part # 567 5575
While the support brackets with the vulcanized rubber is considerably different between the 63/64 62 series, 63 series, and 6039 vs the 75 series and CC and 1959 to 1962, the center member bearing itself is the same:
Bearing Only: 1959 - 1964 (all), 1965-1969 - 75 series, CC : parts group 5.600 with part # 904 778