question - did i miss any markings? specifically outside engine bay? until i clean the whole car it will be hard to see any others. my car been sitting, mostly untouched, since late 70's or early 80's.
On top of the black paint? Yes there are some "missing" from the typical list based on hundreds of other 66 San Jose examples.
As for the ones you found
1st- yellow 32-31 located RH side frame rail.
Passenger side fender identifier. Fenders were placed on an overhead conveyor system similar to what you would find at a dry cleaners where there was a hook and a label about it to identify the hook. Because of this arrangement you will see the numbers repeat over and over again during the production weeks, months and year. Pattern is two or three digit followed by two or three digits and only certain numbers between 0-9 were used in the pattern for some reason
2nd - large yellow D on outside battery tray area inner fender
Typical of all Mustangs built at San Jose over the years as far as location and color used. Can be repeated or applied elsewhere in some less often examples based on what shift built the car and worker assigned to that task was "on duty"
3rd- yellow 21311 located LH frame rail under main fuel line
See 1st response
4th - white 133 & 16 outside engine bay near where hood hinge bolts LH side
Really odd mark location Must be "Fred" again. Believe this was a filler worker that applied this. I would guess that maybe one in 500 or more (over the whole production year) had this mark here. "Fill in Fred" is just a name I gave these markings when comparing them to the vast majority of typical fairly consistent markings we've documented for these cars and others.
If your soda blasting and going slow you should uncover marks that would not have been visible on the car when new. Maybe another half dozen on the front end clip area. These would have been applied to the bare steel to guide painters and other workers during the first "half" of the cars construction
Thanks for sharing - will add them to the pile