bichelle.
In my opinion, the zodiac found some numbered keys that had reference. He did send them as a clue for a reason. He could have had the keys stamped also.
who knows.. Zodiac did have a post office interest as he also sent an earlier message about zip codes in 74..2 pieces of mail with post office clues..

Again, I believe Zodiac had a real post office connection.

Tahoe, Hi back at ya

Thank you! For the info. I appreciate your willingness to jump
in and answer my question and also, the way you present your ideas in a straightforward manner. This makes it much easier for me to digest the information and facts.

the ghost of zodiac

I agree with you in part about the keys. I think he may have sent them in as a clue but at the same time he may have been creating a false clue-to misdirect the investigation.

Welcome to the board, TGOZ. It can get animated at times – but always interesting.

thank You Murray..