Love the color of this pen. Does the color denote a specific year or model? Is this even an original "51" color?

Looks to be a teal blue. Picture makes it look a light brighter than the pics of teal I have seen. It also appears to have a sort of matte finish cap vs. a brushed silver finish.

That has to be Teal, and Teal is one of the original aerometric "51" colors. (Here is a link to my site's "51" profile -- colors are shown at the bottom of the page.)

The cap is Lustraloy, which is what Parker called their matte-finish stainless steel. The only "51" model with a brushed finish is the Flighter:

Richard, looks like a handsome pen. I'm also fond of the bright red and cocoa. Looks like I'm adding to my wish list...

Boy, these "51"'s are addicting!

Richard's site has a great page on the "51" which goes through the various colors here: http://richardspens.com/ref_info/51_profile.htm