I only had one tray pin for the damn longest time, I just used it in the back, and the screw in the front over the trigger held everything in place just fine. Then I found a pin that was quite similar to it while waiting for the bus one day.
^^ I was going to suggest that.. take the one good pin to a hardware store and find a nail with the same diameter. buy the nail, dremil it to the correct length... sand the edges to round off any hard burrs... etc.
(or just pm Jared at destructive customs and I'm sure he could put one in the mail for you for $3... I know.. I just had him send me a few screws.. only a few dollars.. and it got here within a couple days).