I have a colt trooper mk III. 6 inch barrell. Nickel finish....

I have a colt trooper mk III. 6 inch barrell. Nickel finish. There is absolutely no serial number on the frame of the gun, and it has definitely not been filed off. What is it worth, and what should I do with it?

I just recently bought a 6" trooper mk III in blued finish from an elderly lady who's husband passed away. Same think---I can find no serial number anywhere on the frame even under the grips. Where does one usually find the number on a colt? And if the gun has no number what does that signify?? I concur that the finish on my gun is original and no number has been filed or ground off of it.

open the cylinder to find the serial number

discovered it last night. thanks.