John, great info (as always). Were any of those reference points physically transferred onto the car during assembly? Otherwise, how were emblems and other items positioned to the AIM dimensions by the line workers?
(I do understand that the AIM is an engineering document, and not all details were for the worker's use/benefit).
Locating fixtures, drill fixtures, etc. were designed/developed on a match-metal body set up on the surface plate to the design 3-D dimensions with trammeling height gages. It was quite rare to have any locating dimensions called out in the A.I.M. as "on surface" - 99% were expressed in 3-D in X-Y-Z datum format.