It turned out not to be an intro, but a clip from the show. They were playing the "Toccata and Fugue in D Minor" and showing scenes of Bela Lugosi as Dracula and some other things. Then they finally showed Barnabas' portrait and then Josette's, then Barnabas himself with a speech beginning, "I'm alive!" It's been so long since I've seen any of it, but I assume that was when he was first released from the coffin and went to the Old House and talked to Josette's portrait.
Jim Pierson (I'm assuming the same one) was listed as one of the Executive Producers, and under Archival Footage was a credit for Dan Curtis Productions.