Nope.
Walbro and Tillotson both have them.
If you cut a round piece of a pop can that's small enough to fit in the hole, you can plug the port off.
I've heard of people doing it on here, but I've never tried it.
I would imagine Stihl designed them to keep within their power curve, and at the same time increasing longevity.
Be wary that if someone ever substituted a cutoff saw coil, they are limited as well.