Just looking at the photos on this site:
https://www.tcdb.com/Checklist.cfm/sid/25/1952-Bowman, the following appear to be horizontals:
9 - Vern Stephens
20 - Willie Jones
41 - Chico Carrasquel
49 - Jim Hearn
50 - Gerry Staley
51 - Gil Coan
63 - Irv Noren
69 - Joe Adcock
107 - Del Rice
139 - Jerry Priddy
166 - Bobby Adams
174 - Mickey Grasso
180 - Ed Fitzgerald
197 - Charlie Silvera
14 total if I counted correctly.