About the Brattain
I am leery about assigning years to stardates, unless I am capable of reaching a point beyond debate that, yes, this stardate belongs to this year.
We know that this starship was commissioned on stardate 22519.5. However, we don't know what year this is. I have seen 40217.3 applied to 2355 ("The Battle") and 38325.3 applied to 2296 ("The Child"). I think it can be said with certainty that the Brattain
was commissioned sometime in the 24th century; other than that, it's speculation. (I think people assumed that 22519.5 is in 2245 because we know that 23589.7 ("Sins of the Father") occurred in 2346, but this is really speculation, in my opinion.)