Some of the carbon layup may be done in a two step process, with a cosmetic top layer added after the initial layup.

Another trick might be to build a crown and legs independently, then epoxy together.

It is quite possible that the paint on carbon fiber parts not only provides cosmetic coverage, but also hides expected seams and mold marks.

There is likely no structural difference between the fork above, and one painted so that the carbon layup is not visible. But, it does create odd effects.

I looked for some photos of Wilier frames, and didn't see anything quite like the OP's bike, although some photos appeared as if the carbon was intentionally smoked, or greyed.

I don't think there is any structural reason to return the parts, but it is "cheap" if one is paying a couple thousand bucks for a bike that just looks like a cosmetic second.

Is there a reason for customers to accept second rate work? Perhaps returning a few will encourage businesses to consider form, function, and cosmetics.