Posted By:
fkwFor most common cards, Search eBay for pics, or you can Google Images on the Internet.
Most reprints, especially the Goudeys (R319, R320) dont get the color of the back quite right, they are usually printed in black or the wrong shade of green. Also if there is damage or scuffs to the spot between the "GOUDEY GUM CO." and "BOSTON" on the R319 cards thats a good sign it is a reprint as well.
If your cards are all star players, the odds are they will be reprints.
But cant be certain unless I can see a picture.
Frank