I believe they are instructed to keep them but if you get to know someone at the bank... be friendly to the tellers and such, they usualy dont mind looking through the drawr and trading (or even holding for you if they like you that much

) the older bills with ya.
Local banks are usualy good for this, tellers are trained in customer service, if you ask them to do something speacial they will usualy help you the best they can.
In any case... it doesnt hurt to try

-Bobby