You're right midi, the racheting drawbars are the ones that have the detent (i.e., clicks or stops) on each number. However, if you position the drawbarbar in between the clicks you shouldn't get any sound. Whereas the smooth drawbars are "infinitely" adjustable and the particular harmonic sound is present regardless of position.
From what I've read on the Internet, ratchet type drawbars were used up until mid-1954 and then Hammond switched to the smooth type for both console and spinet organs. I'm also surprised that your 1969 B3 has the ratchet type; it may have been modified in the past by a previous owner.
I own a Hammond C2 (with TREK II percussion and 145 Leslie) and it has the detent type. I only paid $975 for it back in 1987 which makes it one of the best investments I've ever made. I wouldn't sell it for any price but I must admit the $200 Native Instruments B4 Organ Simulation Software sounds very impressive.