1970 Kellogg's Proof Card - This is the Only One I've Seen So Far That Isn't in the Set at All

I bought this proof a while back in an auction even though there were some bigger name players available at a similar price.  I just couldn't resist because the card doesn't exist at all in the 1970 Kellogg's Baseball Card Set.

Does anyone know the story behind this card?  Is it on one of the boxes from that year?

Staub never got onto a Kellogg's card.  He did get a great nickname - Le Grand Orange.  If you are old enough or speak French you can probably figure that one out.

I didn't realize that he played from 1963 to 1985.  He had six seasons of 90+ RBIs.  He ended up with 1,466 RBIs, 292 home runs and a .279 batting average.  His only playoff appearance was in 1973.  He did well, hitting four homers. 

He hit five homers off Kenny Holtzman and Phil Niekro.  How did he manage to do so well against knuckleballer Niekro yet go 1-for-25 against Wilbur Wood who threw the same pitch?

In 112 at-bats against Fergie Jenkins he had no homers.  

He was 13-for-19 against Doug Rau.  

All of the above pitchers were good enough to get a Kellogg's card.