Part numbers involved are:
C4DB-6206072 original factory for 1964 Mustangs, ref AM0006 page 16.
C5ZB-6506072 original factory for 1965 Mustangs, ref AM0006 page 16 (same page as above).
C5AB-6306072 original factory for 1966 Mustangs, ref Am0011 page 14.
C5ZZ-65072-A service replacement for 1965 Mustang, may be for 1964, ref Ford Car Parts, section body 47 page 11.
C5AZ-6306072-A service replacement for 1965 and 66 Mustang, ref Ford Car Parts, section body 47 page 11.
Plus this NOS locking version, probably dealer installed C4DZ-6206081-A, ref Ford Car Parts, section body 220 page 5.
See
http://www.concoursmustang.com/forum/index.php?topic=13253.0Can you match part number to picture? Keep in mind: different suppliers; different assembly plants; running changes - all nice "quirks" to keep you (off balance and) busy.
Jim