What is an AC Speedo Reducer No. 6476735 worth because I need to buy one. This is the round style and not the square style.

Hello, Can somebody tell me if there would be a difference in the trans code stamps between a Muncie M20 trans built in October, 1968 versus one built in October 1969 for a 1969 Z28? Recall 1969 was a long model year for camaros so there were 2 October's worth of camaros built in one model...