The model 9-0 Spalding "Three And Out" catchers mitt was near the top of the Spalding catalog in 1916 and sold for $9.00
The bottom of the ad lists a model 9-0P with "Perforated Palm".
Charles King patented the perforated palm design in 1913 for A.G. Spalding. He invented two versions. The first was for small perforations through the palm facing with a cemented and stitched leather backing as reinforcement. The second design was for slots cut horizontally across the palm with the same leather backing. The purpose of the patent design was to counter the slick surface in the pocket so a ball would stick better. I haven't seen examples of the perforated palm variations. They may not have been a big seller since they weren't pictured in the catalog.