Not everyone seems to agree with your account of the requested gap Uzi. I wonder if the company involved in the account backs up the claim?
Anyway, it is funny how the odd numerical designation of F-117 just happens to be the same spot in sequence for the pre-unified number sequence that F-19 would be in the unified sequence. Maybe someone has a sense of humor somewhere.
is the wiki on the F-19. As for the particular model shown here, it seems that perhaps it was indeed just an artist's conception, though there probably is some basis in facts of stealth theory given its form does have stealth potential.
Janes was using F-19 to mean the Lockheed stealth fighter as early as 1984; it would not surprise me if the project got a name/designation change on being nearly outed by Janes. Since a usable aircraft program obviously wouldn't be scrapped for being nearly found out, the only alternative is a name change.