I have seen several ’63’s with black engine compartments. However, I have not seen a ’62 with anything but body color engine compartment. Perhaps your assumption regarding factory location and color choice independence is correct? Maybe only occurred in the ’63 model year?
The acc. entries on the cowl tag are a mystery to me too. They are somewhat explained on a website that discusses many of the ’62 facts. http://home.comcast.net/~oldsfan/MySite/62oldspage.html In my list of information supplied by many owners, the 2M code is also shown on some of their cowl tags and only one of several has factory A/C. So I don’t think 2M is for A/C.
I have only seen 4 cowl tags with the “4-speed syn F-C 200” listed. The website I listed above states the ACC code area was used to alert the production people how to configure the body for special accessories that would follow later in production. This makes sense as the 4-speed syn cars required a special front floor pan section.
In my previous note I incorrectly stated the vinyl top color choice was only white. In review of the ’62 option sheet, it states the vinyl tops were available in white or black.