[swarmee]

Sure, here's a wrapup for newbies to vintage collecting:
1) The card being discussed is from the T206 White Borders set which has 524 different card fronts, covering about 200 different players. Some players, like Hal Chase, have up to 5 different pictures on the front of the cards.
2) The cards were printed by about 20 different brands, and each put their own logo on the back of the card. Some players have 2 or 3 possible backs, some have 15 or so. Some people make a collecting career of trying to get their favorite with every possible back they came on.
3) Some of those companies also made multiple print runs of the cards, during the 1909 season (150 series), 1910 (350 series), and 1911 (460 series). Each of those years may have been printed by a different factory, this one specifically being Factory 30
4) This front picture of Karger has never been seen with the specific back (Sweet Caporal 350 / Factory 30). That's why the original poster (OP) was so excited. If he has a unique card from 1910, it might be worth hundreds or even thousands if real.
5) The OP was mistaken, since the site he bought the card from, posted a picture of the wrong back with his front. So he did not actually have an unknown card, he had a regular common version of the card.

That's the basics of it.