I have never read anything about the Greatest Moments cards coming with a Coin Rub Game card, but this sure looks like it would have come with this set. Here is the picture from the auction, which included the Sal Bando card as well:
The cards are the same size with black borders. The winning bid for this auction was $1,275, so that should give an idea of how rare this card is.
Here is a look at the back.
It does have a similar color scheme as the back of the Greatest Moments cards, but does have a different card stock:
Information on how this set was distributed is very limited. Fortunately a wrapper has surfaced, and recently sold at auction for $3,287.
However, the wrapper does not mention a game card
nor does the box:
However, in searching for images of Topps coin rub cards, I came across this picture:
So with a little research, it turns out that the game card actually was part of the Action Emblems test, not the Greatest Moments set. I just hope the winning bidder realized that they were buying a test card from the Action Emblems test, and didn't think they were picking up a previously unknown Greatest Moments card.