depends on which war you are talking about - the P/F-82 concept came too late for any action during WW 2.
It initially was designed as a VLR (Very Long Range) escort fighter for use in the Pacific (P-82B). VJ-Day came and the Twin-Mustangs no longer were needed. After WW 2, the improved version saw mainly service with the SAC and at times was based in Alaska; also its potential as a Nightfighter was tested and found highly valuable which led to the production of the even more improved P-82F & G-versions.
The F-82 saw much use in the Korean War as Nightfighter and downed a number of enemy planes.
Read here:
http://home.att.net/~jbaugher1/p82.html
Martin