John and Jerry,
Thank you for your responses. Now there is still a bit of a puzzle, especially with respect to my serial number of interest (645002327). Now I have two sources of information which don't align, and this serial number falls into that small area of misalignment.
If there were only 2042 built in 1965 as per John's data from MF, the serial number above would be a 1966 model. However, per the information in Jerry's book, it would be a late 1965 model... Interesting.
Are there any third pieces of information out there?? ;-)
Cheers,
JB