Awesome! Welcome to the boards! Is your grandfather pictured in one of the photos you provided? That would be incredible provenance!
My advice:
Go to this link:
https://www.psacard.com/services/aut...uthentication/
Follow the 4 steps listed and send the baseball via insured mail or Fedex to PSA/DNA. This will be the best service to maximize your investment. By investment I mean your time to research PSA/DNA and the time to get it sent to them and of course the cost of authentication.
I personally would not have it slabbed in a PSA/DNA ball cube. You can do that yourself for less than $5 (ball cube).
Your total cost might be under $400 with shipping to and from and authentication but you could spend more if you are impatient and want it back quicker.
Beautiful item BTW! Thanks for sharing!
Peace, Mike
PS Babe Ruth fee is $300 from PSA/DNA to have them look at it. If its real then its $300, if they consider it "not authentic", its also $300! My hunch is that your $300 will be well spent!
You will also have to pay the premium item fee of $25 since I assume you will declare its value more than $1000. They will ask you if you want a Full letter upgrade for $10 but just ignore that because your authentication fee is so high, they will provide a Full Letter if they determine it authentic. Good luck and please share the results when you get this museum piece back!