I would say the same, I have only seen blank backs as part of the sheet. I have about 20 stat backs and no ad backs, the stat backs are pretty cool and the ad backs are boring to me in comparison.
Always looking to add any track and field that I don't already have!
This set was produced a company that used to operate a block from my first job. Made me wonder, if I snuck into the basement would I find a couple sets tucked away and forgotten for 90 years
Best,
Ed