No bull trout in fourmile....not a splake either....splake are nothing more than genetically mutated theme park monsters....the ODFW doesn't stock them....they don't occur in the wild, I don't think 4-mile brookies are gettin' all JIGGY with stocked lakers! What you have there is a naturally reproducing, quality wild fish!!! David say's he would have taken it home and ate it!!!
Nice fish! It definitely looks like a brook trout, and not a bull or laker, with the red fins that you pointed out. I've never caught a splake, so I can't tell if that is what it is, but it is at least part, and most likely all, brook trout.