Renaming: Assuming that the package name is different from what you're editing, just Ctrl + F for uiName and change the value.
Recoloring: If you're doing an edit of the default gun, pushbroom, or various other weapons, you might not have to do much. Ctrl + F for colorShift, and if doColorShift is true, then change this line:
colorShiftColor = "r g b a";
to your liking.
If doColorShift is false or missing, insert that line as well as the doColorShift one under the item datablock.