One of the things that we need to do is create more technical descriptions of things.
There are technical papers that describe gloss levels, but instead we say "Semi-Gloss black, a bit on the glossy side."
Jim has a wonderful description of fasteners in the Library which has served us all well.
But we don't have a glossary of the various bolt marking and instead say "SEMS" or "==".
Agree no we don't and Jim and I have discussed the idea of adding that detail a number of times.
Of course producing a spread sheet with that information would mean possible 5 times the space and work of the original effort since the head markings can, depending on the part differ between the plants and differ from different production periods. One good example as been the fender bolt studies that have been presented on this site.
To the rescue on the Nevada SAAC site is a picture of the various head markings with standard numbers.
http://nvsaac.com/Details/nuts_bolts_headmarks.htm
Don't believe that was an original work by the owner of that site. Appears to be a reorganization or an earlier graphic version of the one published in the AMK Guide to For Fasteners 1955-73 down to the introduction/text at the beginning. In the AMK version this takes three pages of the book. I believe the publications was based on the Utility Catalog title that Ford used for these publications back into the 30's at least
Bottom line , yes it would be great if someone would dedicate a few years to getting this collected or getting the ball rolling by taking on the task. Expect that there would be a lot of "unknown" in the spread sheet for a good while as you hunt down examples from every month or even tighter time period if there was a change, from every plant as well as from original cars. Task gets more difficult everyday with especially eastern cars were owners are just replacing all of their hardware with the replacement stuff.