The B-2 rollout was in November 1988 (only a couple of weeks after the F-117 unveiling) and was a public occasion at Palmdale.
There was apparently much speculation about its planform on the day, as the press & public were seated such that they could only see it from the front, until:
(a) Aviation Week revealed that they'd taken photos from a rented Cessna flying overhead.
(b) People twigged that the "Air Force star" on the concrete in front of the jet was in fact...
(Yes, I know you can see its shadow - but it's a good story!)