TH 400 mystery

[@wot]

I have a 70 Nova, with a build date of 09A. The TH400 in the car has a small metal tag that reads 70 CA 325. This would indicate the wrong code for the L78 automatic, plus, it puts the buils date of the transmission after the build date of the car. I assume it has been changed. I have the POP. a partial broadcast sheet and some past title history. All the numbers on the car are in order except the transmission . Now to my question. The POP lists the transmission as 70W437. The W would be correct, but the 437 puts the build date 6 months after that of the car. Is it possible that the toriginal tranny was of a 69 production run? Any help would be great.