1969 Topps Football card back question

[Directly]

Rack pack showing card backs "RUB EDGE OF COIN OVER BLANK SPACE--was this caption just on certain cards--???

Thanks!

[toppsman]

I'm pretty sure the different backs only apply to 1969 FB second series.

By my count 34 of 131 second series cards have the "rub coin" variety.

Also ten of them form a puzzle of Fran Tarkenton.

[Directly]

Appreciate the insight--Thanks!!