Posted By:
MWLeon,
Based on what the hobby has yielded thus far, I believe the distribution between ad backs and bio backs to be roughly equal with the majority of the ad backs coming from Alan Hager's find. The lone 1927 Spalding (Babe Ruth) is a bio back with slightly different verbiage and a copyright date of September 1927 instead of November 1926 (See image below).
