Perhaps someone else picked up on this, but in case they didn't, DID THEY HAVE ZIP CODES IN 1972? The letters all have a zip code at the top. I don't remember zip codes that far back.
"Perhaps someone else picked up on this, but in case they didn't, DID THEY HAVE ZIP CODES IN 1972? The letters all have a zip code at the top. I don't remember zip codes that far back."
Yup. ZIP codes were introduced in 1963, made mandatory for bulk mail in 1967, I believe. They were in wide use in 1971.
Zip codes use was atarted in 1963.