Vintage Chinese Chess Set origin unknown

I'm not sure if these are ivory , bone, or other material. My cousin bought these at an auction house in Chicago in the late 60's and had them stored away until now. I took pictures of them 140, and are available for viewing at the Nikon site below.

NIKON IMAGE SPACE
http://img.gg/dQONvkC

I noticed the base of each piece appears to have drill marks as some kind of coding? Or, maybe these pieces were not finished and the bottoms would be ground or shaped to the buyers specifications.