I had five different silver paint pens and small touchup bottles which I tried. None were really close.
Then I pulled out my bottle of HWP101 Silver and it was VERY close!
What I do is shake it real good, spray a bit of it into the cap and let it sit for about 3-5 mins to dry out a bit. Then I use a really good small touchup paint brush to touchup small scratches. You can get the can for $7 or so at auto stores and Wal Mart.
(Can anyone point me to a touchup match for the sidecovers on a 2009?)
I found an even better match than the above Color Rite. It's called Rust-Oleum Metallic Brilliant Metal Finish: 7271 Silver Metallic. It's available at Walmart and looks better than the Color Rite. If you're going to touch it up with a brush make sure you get high quality brushes, not the cheapos.
A spray can of Krylon Fusion for plastic in flat black is ideal for restoring any of the faded black plastic pieces on the bike. Also works well on Givi luggage. It adheres really well and makes it look better than brand new. Best part is it is cheap.