The best I could find are: pin dimensions- 15inches high, 4.75 inches wide.
Would you believe that the ABC/WIBC do not list the pin dimensions in their rules?
They only address 'markings, labels, and coatings'.
However, here is what more web searching did turn up: ABC/WIBC weight specification for bowling pins used in sanctioned competition is 3 lbs. 6 ozs. minimum to 3 lbs. 10 ozs. maximum.