OK..sounds confusing...let's see if I can't confuse it even more...
I thought the "A,B,C" profile necks were not used until after CBS bought the Company. All the L and pre-L Strats I ever worked on only had the manufacture dates pencilled on the end of the neck.
CBS used a stamp with the date and neck shape with necks bearing maple or rosewood fingerboards. This was used on both 4-bolt and 3-bolt necks.
Interestingly, Leo did not offer maple and rosewood at the same time.
My reference to the "U" profile is because the post65 "C" shape is broader than that of the pre65 Strat, but not quite as thin as the "B" - so I refer to it as a "U" shape.
look forward to your reply
Peter Mac