Obviously, the sear nose is hardened. I would guess that the rest of it is, too, as that would be the simplest way to heat treat the part. You could probably tell if you can bend it cold, without first annealing it, by trying to cut the sear bar near the bend with a file. Try this on the top of the sear bar, where you won't roughen up any of the sear that moves against the lock plate or trigger bars. If the file will cut the sear bar, you should be able to bend it cold. If you need to anneal it before bending, clamp the part from the swell around the screw hole to the nose in a vise and heat near the 90* angle on out to the end of the bar where the triggers contact it. If you use aluminum jaws in the vise you won't scratch up the part where it rubs against the lock plate and bridle. They might also help absorb some of the heat around the part of the sear you don't want to anneal.