Can I use a "corned" beef brisket recipe for "beef brisket"?
Brisket is the cut of beef. Corned means it has been cured in a brine with seasonings. I don't think corned beef would do as a substitute for the untreated meat.
My gut reaction is the same as Susan's but I can't think of any reason you couldn't try it if you were so inclined. The results would certainly be something other than what the recipe intended though, and I'd avoid adding any additional salt until near the end.
I would NEVER use corn beef for a brisket of beef recipe. The corn beef has been treated and would be radically different in taste from the recipes intent.