BudShort, the finger holes with the curve in them was known as the Curval grip. The Bates and Curval and Flat grips were drilling methods done by Ebonite in the 1940's and featured types of curved And flat finger and thumb holes.
These are old time technology for conventional ball grips, there were also fitting balls and ball drilling jigs designed for these. Also promotional items like balls which had bates grip and curval on them.
The Bates Grip was designed by Sulley J. Bates back in the 1940's. The main feature was that the finger and thumb holes had flat sided holes for gripping the ball.
What the Bates Grip basically did was to allow the fingers and thumb spread out in the holes. Today this is what we use oval holes for.
The Curval grip was when the finger holes were drilled, inside the hole at a certain depth the holes would curve under the grip.
The ball pictured might not be the same color but this ball might be close to the age . Late 1930's and 1940's.