There appears to be a conflict in use for 67. The base number, 6C038, does not appear in the 67 Chassis Assembly Manual (same for 68) on the motor mount page (As a reference, it does appear in the 64-65 Chassis Manual motor mount page as 6C038). The full service part number, C3DZ-6C038-A, appears in the 60-68 MPC as being used on 289 2V and 4V engines (221, 260 as well - no HP) for Mustangs, 2 each; the 65-72 MPC (75 ed) shows 289 4V, 64 thru 67, 289 2V, 64 thru 68, essentially the same.
Service say "yes", assembly say "eh".
Jim