TromboneChat

I recently purchased a few dozen instruments at an estate sale. Mostly guitars, but a few generic newer trombones and a couple trumpets. One of the trombones appears to be quite old. There was a luggage tag inside the case with the name and address of a local man who I had met on many occasions. He graduated high school in 1947; I found his band photo in the yearbook. I don't see any model name anywhere, only the number 430. It does say "GRANDS PRIX" and I have read that some Selmers were known by that name. I also read it was very difficult to determine the manufacture date on these. Any information you would be willing to share would be appreciated.

"Grands prix" isn't model name of trombone.
Below are names of 2 cities with years of exhibitions, where and when this trombone model received Grand Prizes.