I like that it says MIGHT be the 3rd ever made. Even if it was I'd still guesstimate the value around $300 max.
PROS
It is old, it is in great new condition, it includes all of the paper work.
CONS
It is a bowling ball. It is rubber.
Urethane and reactive bowling balls that are in this condition fetch a higher price because if drilled they can be very usable. This ball will roll, it will knock over pins all the same. It just will be ugly in the process.