And the BDA has been made & offered much more recently than the 1990s.
According the the Fjestad Blue Book, the last BDAs were made in 1997. Maybe you encountered new old stock? It happens.
I bought a NEW Sig P-210-6 in 1997 that was made in 1976; it apparently spent most of those two decades on a distributor's shelf.
I bought a NIB S&W 547 in 1998, and they were last made in 1985.