From the June 1968 MPC, see attached.
There was no C7AZ-2884-A being serviced as of this date. Even the January 1967 MPC is identical.
Both the -B and -C versions say they for the "hang-on" air conditioning, not the integral select-air type.
Do you have hang-on or integral? Probably integral since you used the term "factory", and I think that for 67 the hang-on type was limited to dealer or aftermarket.
Assuming integral with a 6 cylinder, it looks like the correct one is C7ZZ-2884-B. See the second picture. The description says the metal tag would be listed as C7ZA-2891-C, 6.875" OD, and double sheave.