According to the 1967 Electrical Assembly Manual,both screws are No. 10, 16 threads per inch, pointed, self-tapping, hex, washer head screws, 3/8" long. The Standard and Utility Parts Catalog does not address the head size. However, the "Industry Standard" for No. 10 screws is 5/16" (in Jeff's pictures, these do appear to be 5/16").
Note also that the screw that holds the ground wire should have a No. 10 external lock washer under the ring connector.
According to the Assembly Manual, both the screws and lock washer should have a zinc dichromate finish. The Service Parts are shown with just a zinc finish.
Hope this helps.
Bob