Hello, first-time poster here. I primarily collect pre-war vintage items, including game-used, but recently purchased a couple of modern footballs. As a result, I was digging around looking for information on how to photo-match NFL footballs, and found an old post that describes the marks that various officials put on balls: http://www.gameuseduniverse.com/vb_f...1&postcount=11

The other information in the thread was also very helpful;e.g- explanation of 2-letter codes for determining when the footballs were manufactured. Has any attempt been made to create a more encompassing list? Thanks.