It looks like the seller has a bunch of other cards for sale. Interestingly, of all the other cards of his (assuming it is a he), they all say "original" under the original/reprint heading.
The fact that this one was marked as unknown feels sketchy to me. Especially as he has it labeled like all of his other cards. I would return the card. Hopefully if paid via paypal you did with a credit card so you can dispute the charge as a last stop backstop.
This is a part of a broader thing that I am seeing on eBay. People listing cards that the the title seems to indicate the card as an original, but buried in the description you see stuff like: "I'M SELLING THIS CARD AS UNKNOWN TO WHETHER IT'S A REPRINT OR ORIGINAL SINCE IT'S NOT BEEN GRADED OR CERTIFIED. HOWEVER CARD IN PICTURES IS EXACT BEING SOLD."
What is difficult is that
I so want it to be real and have it be my version of a "barn find" on ebay. Stay away.
Here are some good examples. One of my personal "whale cards" is a 48-49 Leaf Satchel Paige. I love the look of the card and I would love to own one. If you look on Ebay you see:
http://www.ebay.com/itm/1948-1949-LE...AAAOSwSdZWdtYr
http://www.ebay.com/itm/1948-LEAF-LE...wAAOSwUuFWv70B
http://www.ebay.com/itm/1948-1949-LE...AAAOSwSdZWdtYr
(The example above sold for $305!)
http://www.ebay.com/itm/1948-1949-LE...AAAOSwSdZWdtYr
http://www.ebay.com/itm/1948-Leaf-8-...wAAOSw3KFWeMv5
etc.