Cannot be found elsewhere on the Internet.
Showcased below is the 20th Anniversary Buybacks card that I acquired from my 2009 Upper Deck Series 2 Baseball hobby box.
Showcase
Series: 2009 Upper Deck Series 2 Baseball.
Set: 20th Anniversary Buybacks.
Card: 1989 Upper Deck Baseball 770 Greg Briley.
Condition: Near-Mint to Mint.
Images:
Notes
Upper Deck claimed that all 800 cards from their 1989 Upper Deck Baseball series was stamped with the 20th Anniversary Buybacks logo in even quantities that wasn't detailed further.
One collector claimed that since 2009, they purchased four 20th Anniversary Buybacks of the same card, and saw one more copy for sale.
With no official word to go by, it appears as if Upper Deck produced at least five copies of each card in their 20th Anniversary Buybacks set.
Value
I couldn't find another copy of that card on the Internet, which is odd considering that series is over 6 years old. With nothing to go by, I'm going to list that card on eBay for $19.99 or Best Offer.