QUESTION to the experts.
Car build period was:
01 = January, 1967, the month car was built.
D = Fourth week of the month.
That means dates between: Monday 01-23-67 to Sunday 01-29-67 correct?
What date was exactly stamped on my original 67 transmission for my car?
That date is when the build period started. Figure a few days afterwards it was completed providing it didn't get pulled to the side for anything out of the norm. I haven't looked at the Julian date calculator to see if your day dates are accurate. As an example of a 'period' my 67 has a 4B date on the trim tag and the UOIT shows a date of April 13th. Almost at the end of that period.
But, don't get hung up on the tranny date stamp. The date stamped could have been several weeks before the car build date and sat in inventory before being used. The fact that it will not be the original tranny will not make any "P" date any more valuable unless you happen to find the real case with the VIN stamped in it. Most cars today do not have their original trannys so it will not impact the value of the car much at all if you plan on selling it later.
Don't worry about the tranny and just enjoy the car while you have your health and some $$$$ in your pocket. Life is short!