Nail,

You can buy the factory (Remington) replacement from Brownell's. I'd guess that would match closer than any of the other ones. It's also cheaper and comes with that cool looking fluted firing pin (not that you can see it once it's installed).

http://www.brownells.com/.aspx/sid=26508/pid=0/sku/Firing_Pin_Assembly__SS__SA

-Dan