JD- I've used that trick a bunch - what a life saver for me - I forget where I learned it too... must have been here. Another trick for holding a sight came from Don Getz IIRC - bend a thin section of brass or steel into a strip about 1/2" wide, 2" long, with a 1/2" elbow. Clamp the long end onto the barrel and slide the sight underneath the elbow and it'll stay put while you solder.
Dennis - I don't know how the gun was blued, but as an experiment I blued half of a scrap with perma-blue, then heated the middle until I saw the spectrum of colors from straw through dark blue appear on the polished side. The blue was pretty much unaffected by the lower temp colors and changed darker with the higher heat colors. Since you won't be going much above 400*, you might be able to get away with soldering. Just food for thought. I'd be more concerned about scrubbing away the leftover flux afterwards.
No experience with the epoxies, but have had some industrial strength CA glue work miracles before.
