I've seen that link and it's dated 2002. I thought they discontinued the B-20 when they introduced the B-26 as it was "new and improved" I do recall, leadbottom now that you mention it, that they allegedly incresed the piston diameter from 25mm to 26mm as part of the improvement. But some have said that they (the B-20 and B-26) use the same seal, and piston, so they didn't increase it any. I know the B-26 has fiber optic sights and the B-20 was non fiber optic. Maybe these are old warehouse stock that turned up somewhere.
Nathan