I assume the return address was correct on the label you originally printed? In any case, it sounds like you won. If you can track down the memory, then you win 2x.
Yes the correct address was correct on the original label. Not sure if that memory can be tracked down at this point. Depends on who ever received it doesn't keep it or not. If they do the honest thing and take it back to the post office the mailman said it would be most likely returned to sender but they're opening a case anyhow to track it down.