Classic/Antique Car Repair: transmission decoder, mustang ii, c4

Question
I have a 68 mustang with an unknown transmission. I found these numbers on the transmission. Ford (RF-D4ZP-7A040-AA)
Trying to find out year, C4 or C3 3spd auto?
Thank You

Answer
The best that I can do with a part number instead of information of the transmission tag is that it was built in 1974 and was original for a Mustang II which would make it a C-6. The AA at the end indicates that it is a revision of an earlier transmission.
Brad