We never made a separate product for the B2K, I'm pretty sure we made a "Predator"-brand drop-in for it but that was all it was ever called.
Still have that cocker? I miss it. I tuned that marker to fire smooth and perfect, with every aftermarket shiney-dodad I could find. I hope it has given you good service. I might still want to try and buy it back from you .. hmm..