Below is a link to an article on Mike Dolbear's site written by Bob Henrit (Argent, Kinks, etc.). By the way, Henrit was one of the drummers who's playing I enjoyed in the "old days."
It's a great read about drums and the drum business in the 60's and 70's, and may shed light on some non-factory hardware configurations on the vintage drums we occasionally see.
It also gives the source of the chain drive pedals offered by most companies these days.