Believe the correct one (from looking at other K code automatic 67's) would be the C code as in 66. Don't see why Ford would go to a standard trans with the softer shifting. In 68 this was changed to what was the heavy duty C4 application for that year using the "H" servo. Believe you will find that judges will be looking for that "C"
Would guess that like most, the trans was rebuilt and exchanged rather than using the original. Someone likely got your high performance one in an exchange or the trans shop saved the good parts (like what happened to many a hipo head) for another project
These servos, with the governor and spring, are not easy to find and there was a reproduction available at one time. One just recently sold on Ebay last week