Once you've put a sword in the hand, and parented, you can save it to your Props library. You'll get a message asking if you want to make it a smart prop. You can say yes, and that sword will always come out into the proper hand when you load it. Of course, you may want to save the sword under a different name than the original, to be safe. Many good props are already smart props which means they will automatically go where they should!