Ignition lock cylinder install

That is strange Steve when I ordered my replacement 69 there were only 2 part numbers for in dash locks , 1 of those must be a very old model year , like pre 49 the 67 and 68 both are supposed to be the US50L part # and some references say 49-68 and some say 60-68 . I know the vans went back to that lock in 70 as well as any trucks that had dash mounted switches .