The Bausch & Lomb 75mm f/5.6 Telephoto lens produced for the Argus C2 and C3 cameras is an exceedingly rare item. According to Lahue and Bailey in Glass, Brass, & Chrome (see References), B&L manufactured the Cintar f3.5 50mm anastigmat triplet lenses in 1938-39. Very few 75mm lenses were produced for a brief time with the B&L name and were never put into regular production. These lenses were provided to dealers but were available at prices that rivalled similar lens from Leitz and Zeiss.
Phil Sterritt was kind enough to share information as well as several images that together make up the bulk of what I know about this rare lens. As can be seen above, a few C3 models were specially fit with the 75mm B&L lens. The lens required adjustments that matched the 75mm lens with a particular C2 or C3 body.