I think you should at least price the two options. There are always a few diehards who will want it 100% accurate or not at all, as well as those that are okay with it as long as the external look is correct.

As a footnote it looks like the glass is pretty convex anyway, so I wonder how much adjustment is really even needed? Kind of like those $3 blind-spot stick-on mirrors which work well regardless of where the main mirror is pointed.