Believe it or not, I just visited the thread to find out the exact same thing!!! I have a few in an exchange and I was worried to withdraw to an (maybe) older version of wallet..
as long as you backup your wallet.dat you will be fine, the amount of coins your public address have is recorded in the blockchain (which every user running the synced client have a copy of), and the private key to prove that said public address is yours is stored in your wallet file.