As one who performed warranty service and repair on the E and I frame Colt's, I would suggest that the owner leave the gun alone. If some of the parts are "polished", that may be enough to cause timing issues.
A reduced mainspring, if still available, may give a better feel, but may cause misfires.
I have worked on many of them, and would be willing to tune it, but still stay with my original recommendation. A bent yoke can cause a poor double action. Open the cylinder and snap the gun enough to get a feel for it. Then do the same with the cylinder closed. If no difference, the yoke is okay. Leave it alone. If the action deteriorates, the yoke is likely bent. Colt's will still work on your gun, but you won't care for the price or the turnaround time.
Last but not least, make sure the sideplate screws are tight.
A Smith Model 14-6 38 Target Masterpiece limited run will out shoot about any revolver ever made. See pic above. They were a small run (2000) through the Custom Shop a long time ago, and don't go cheap. I have seen four in my life, and have owned three of them. The two I have now are not for sale. I have never had anything that would touch them for accuracy. The K frame gun with the full lug L frame barrel combines the best of both worlds.
