1970 Kellogg's Baseball Card Proofs - Just a Few of the Kellogg's Items From a Recent Auction

As mentioned in an earlier post, I made a few mistakes with my first attempt at bidding in Beckett Auctions.  I did purchase a few 1970 Kellogg's card proofs.  These will be mentioned in future posts.

I ended up purchasing the Reggie Jackson proof shown below.  I was quite surprised that my early bid ended up being the highest bid for this great card. 

The other proofs that I purchased are near and dear to me, but this Reggie Jackson may not stay in my collection.  I might need to sell it to pay for my other purchases in the auction which will show up here sometime soon.

I haven't seen these proofs for sale often and I have no idea which players are available as proof cards.  If anyone can point me to that information that would be great.  There are no PSA graded 1970 Kellogg's proofs.