I hope I am allowed to add a link here... This will hopefully give you a better idea of how all of this began.
As for the SF Giants didn't they start off as the Gothams? If so I have a few letters from that time period. I really don't know enough about any of the teams to say for sure if they were the Gothams though. I am learning as I go.
https://www.antiquers.com/threads/he...ele-box.61531/
Here's one more link too...
https://www.antiquers.com/threads/we...ele-box.61542/