Sturgio,
Chromeslayer,

Look at the spot pattern. Coastal cutthroat spots typically extend well below the lateral line compared to Rich's specimen. The black margin on the adipose is also more typical of rainbow/steelhead. Also, a cutthroat that colored up should definitely be showing off its red throat slashes. Of course, the two species are so closely related that we'd have to do a chromosome count to really be sure.

Easylimits,

The spots on your cutthroat extend further below the lateral line than on Rich's fish, and the spots are proportionately smaller as well.

Sincerely,

Salmo g.