Usually a date on a lock refers to a patent date, but I could not find a Sargent & Greenleaf patent on that date (in fact, it appears not to be a Tuesday, and US patents have always been issued on a Tuesday).
As mentioned, pictures would help. From the description, this is probably a low-end S&G lock because of the combination-changing mechanism. A safe/locksmith might be able to repair the lock but you have to decide whether to restore the safe using the original lock, or replace the lock with a newer one which would be more secure and easier to change. The original would probably be OK. Just be very careful it’s working properly before locking the door!
