Brake shoe question.

Hello all I am new to this site. I went to a estate sale and bought a box of "Gamble-Skogmo" brake pads from 1930's - 1950's. My question is that some of the shoes seem to fit everything from Buicks to Willys. Did shoes fit all kinds of cars from different manufactures? I tried to google the numbers on the boxes and nothing. This company is long gone. It also has Varcon on some of the boxes. I can not find anything on the internet about these shoes. The one set of shoes has a pamphlet that has about 20+ cars that they fit? Thanks for your help. And come to the Woodward Dream Cruise, the madness has already started!
Mark

Very rarely would one set of shoes fit many cars of different mfg., maybe within a specific carline, but Ive never seen this across manufacturers, not from the 50's up.

Actually i never encountered this before, Maybe it is really rare.