Actually, in the 1968 Rick catalog, of which I now have an original copy, it lists ALL 4000 series basses as having 21 frets, although in reality all 4000 series had only 20 frets in 1967 and 1968. In fact the only year any Rick basses have ever actually had 21 frets was a brief time in 1970 and the first three months or so of 1971 (I own one of these 21-fretters too, a Jan 1970 one, too). Whomever is responsible for putting that catalog together at Rickenbacker in 1968 apparently is listing the nut as a fret, I suppose, or else is engaging in very "creative" marketing

Click below to see the actual page scan from this catalog, showing 21 frets for the 4005 and others:
http://www.elysrand.com/rick68p7.jpg
Comments, anyone?

Do unto others as you would have them do unto you, and sit in with the band whenever you can, to keep your chops up!