I can't grasp what you have in mind as "more precise." What do you mean, different metal, or different shape?
Your gunsmith should be able to make up anything (within reason) that you can dream up. Pretty simple to mill off the sight blade, mill a groove into the base and fabricate whatever you want and pin it in the base.
(By different metal, I meant something like German silver or brass instead of the blued steel.)
Here is my Uberti with a German silver front sight: