An 03A3 that hasn't been rebuilt is pretty rare. In re-build, they didn't pay much attention to keeping the zero on the index -- as long as the rifle could be zeroed, that was fine.
The first thing to do is shoot the rifle. If it shoots as you expect, that should be good enough. If you need to adjust it, there are two ways I like -- first of all, you can easily make (if you cannot find) a new front sight that is lower or higher than the one you currently have.
Second, if it shoots high, I like to put a blob of epoxy on the sight, color it with typewriter correction fluid, and make a good, easy to see hunting bead.