On Facebook -JOIN I Antique Online.com: Collectors of Antiques and Collectibles.
Here is the link for the group https://www.facebook.com/groups/327133184409134/
Please join our FB group where YOU can post directly.
A Community For People Who Buy, Sell or Collect Antiques, Collectibles and Art
I think I remember these. I'm thinking my Dad had something like this. I want to say it's related to the AAA, where your car would be issued a number, I think by the triple A, but it might also have been the DMV, Can't recall. Anyway, if your keys were ever lost, someone could simply drop them in any mailbox in USA and they would be returned to you!
That's the best I've got for ya! :)
This is an excerpt from a conversation on Reddit...
"Looks like the tag the put on new car keys, with a code number for duplicates."
"I second this."
"Locksmith, can confirm. Code is most likely for a Mazda, Nissan, or Toyota. Knowing the make and model, plus having this code allows a locksmith to cut you a key, even if you've lost all the originals. If you ever buy a new car, get the code and keep it someplace digitally, it might get you out of a bind."
Just something to think about, but that is how I am leaning.