If you order a book that has different printing years, and say I order the one printed in 2003 instead of 1999, if that book doesn't get accepted from that person and it goes to the next person in line, does that mean I still may get a book that was printed in 1999?  That probably shouldn't have been a whole sentence, but, you know....Thanks all!

If the 2 printings have different ISBNs, then, no you should not.  If the first person does not respond or cancels your request, it goes to the next person that has posted that specific ISBN for trade.

Oh, yeah that makes sense.  I wasn't thinking about them having different ISBNs.  Thanks, Sarah!

Some books get reissued several times with the same ISBN.  So if you want a specific cover you should put that in your conditions.