(24800-36) seems to be a thin, concave spring-steel washer that went under the nut. (24800-36) is obsolete. I'll motor over to http://nosparts.com/
and see what they have. The OEM (24979-36) nut and washer seem to be one-piece, where the nut was dropped into the crankcase and then the bolt was then turned into the fixed-positioned nut. The '41-57 cases have the same hollow cavity for the nut and lock washer.
the nut is missing the pointed pinched on washer with the hexagon hole, to prevent the nut from turning instead off having to take off the generator to reach the nut with a spanner.
I found one in the "Knuckle" crate. We still need the 24800-36 concave spring washer. I measure that it's 5/8 x 3/8 x 1/32".