It's quite probable 902 is the serial, if by the "base" you mean the back of the bottom end of the lower keyed joint. If so, it's from 1928 or so.
For value, look up "Buffet pre-r13" on ebay, and add a few hundred to whichever is most like yours and is in similar condition. (As all that sold recently are in Bb or Eb, not A)
Additionally, there's an A like yours, a year or two later, that sold for $454 back in August. (Which to me seems low. Probably because they didn't mention who repaired it, and that there's no indication that the barrel is a buffet, which tends to be important for value-most people want the original barrel with their horns.)