It does sound as though the flight hasn't passed to 'airport control' yet - which can be for all sorts of reasons including a delay to the previous day's flight.

Keep checking OLCI if you wish; it may clear and let you issue a boarding pass.

If not, and your ticket number is showing (as you report), and the flight isn't zeroed-out, then the chances are that you'll simply pick up the boarding pass at the airport in the old-fashioned way, and find it bears the seat number that you pre-allocated.

No bonus, but should be no real cause for alarm either.