1921 E121 American Caramel Series of 80

[ls7plus]

As I'm sure many of us already know, the 1921 E121 American Caramel Series of 80 cards come with two different backs: the first, and most common, has a first line on the back of the card that reads "This set consists of eighty of the...," while the scarcer back's first line reads "This set consists of eighty..." Several questions come to mind here:

(1) how rare are the second version backed cards, compared to the first?

(2) is there now or would you expect there to be in the future any significant premium attached to the scarcer version back, as we all know what's happened with rarer T206 back variations?

(3) does the back variation exist with every card in the set? I would think so, as the variation probably reflects a separate and distinct printing of the entire set.

Certain coins with less obvious variations have done quite well over time, value wise, after extended periods where no significant premium was initially attached to the rarer variation.

After visiting his website, I know Rhett is probably one of the most knowledgable collectors on this subject, and it would be interesting to get his imput.

As always, all thoughts are appreciated.

Larry