I found this
There will be 6 digits on the reel foot. An example might be 080400. Reading the numbers from left to right......The first two numbers of "08" are for the month of (August).....The third digit will always be a "0" indicating the number "6" for the 1960s decade. The fourth digit in this example "4" is the actual year of that decade, 1964. The last two numbers "00" would reflect the number of revisions made to the reel which are none in this example. Another example might be 120501. (12) December (05) 1965 (01) revisions.
There will be 6 digits on the reel foot. An example might be 080400. Reading the numbers from left to right......The first two numbers of "08" are for the month of (August).....The third digit will always be a "0" indicating the number "6" for the 1960s decade. The fourth digit in this example "4" is the actual year of that decade, 1964. The last two numbers "00" would reflect the number of revisions made to the reel which are none in this example. Another example might be 120501. (12) December (05) 1965 (01) revisions.