As Kevinski and gmc' said, its the rubbing block off a newer replacement fuel pump actuator arm (first image, AC 4666, non-glass bowl). The original pumps had a different style, laminated pump arm, that doesn't include that piece (second image, AC 9797, glass bowl). Both pumps shown in the images are NOS units.
Apparently, the pad from a pump used on your engine separated from the fuel pump actuator and dropped into the crankcase at some point in time.
