Hi Richard, BSA/TRi group policy was every thing was an extra ,enc rearchaincase ,dual seat (on some models ) and pillion pegs and tacho all extras even on a bonnie , there sales order form had a complete section for extras .Even in the sixties you were only adding a few pounds for each item but when added up made a difference . It helped there advertising, price wise, as they only quoted the basic price in the adverts making the bikes more competitive. Cheers Bob