You can find on a number of early 3rd Gens that what you have is a 2nd Gen slide that has been partially upgraded for a 3rd Gen pistol. These slides are easy to ID as they have the four lines of S&W information on the left side of the slide and these early guns tend to have a finish that more closely aligns with 2nd Gen guns than with the 3rd Gens.

These guns use the old style 2nd Gen simple blade fixed rear sight or the large winged adjustable rear sight. The adjustable rear sight between 2nd and 3rd Gens is the same.

The front sight is built up higher for the adjustable sight guns.

While I get the hobby/project side of your idea, it sounds cost prohibitive for very little tangible result to me.