Hey Chris, there's something called the body number plate, which is not the VIN plate. It should be under the hood, riveted above the wiper motor, near the firewall (to port side).
Find that. Then starting at top left, you should have a letter, a space, then two numbers (no space) then another letter. First letter is the year, my 85 if an "F", so yours should be hmm… I don't know. "A" would be 1980. Model year should be last letter in your VIN, then there should be 7 numbers.
Anyway, first two numbers on "body number plate" should be month (01 = January, 02=Feb, etc.), last letter should be the week (A is first week, B is second, etc). Any help?
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Perhaps the coding changed in 1980?
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Thanks to my handy Haynes manual :suspense: 1980 was indeed "A", and 1979 was "9", 1978 was "8" etc.