barn door hinges?

[rossboss]

I know that the top hinges are different then the bottom, I believe that the bottoms are physicaly longer. Is there a difference from one side to the other.
I'm being told that the bottoms will only go on one way and the door pins are pointing up. That doesn't sound right to me, I pretty sure all the pins were facing down when I dismantled the doors. Would someone look at there door pins and let me know what direction they are facing.