You are correct,,The striker knob was sometimes removed in conversions to sporters and target guns to speed the lock time.

N/Match guns were offered with that feature done at the arsenal at least for a time.
IIRC the N/M rifles had a stronger firing pin spring in them as well to again speed up the lock time. I don't know if that was all of the N/M or just the headless striker type.

That striker knob actually served as a safety feature on the rifle. To divert any gas from a ruptured case/primer that could have made it's way that far back and out the rear of the bolt via the striker rod. The shape of the knob defected the gas to the sides at least somewhat. Instead of directly into the shooters eys and face.

That style damascene application is the same feature you used to see on the slide way beds of machine tools and other precision moving parts.
It very slightly impresses the surface ( couple ten/ .000") where applied and allows oil to migrate on those surfaces. That makes for a smoother and easier movement betw two very closely fitted parts w/o reducing either one or the other in their over all dimension.
It's done with a hardened steel tool shaped and highly polished to a rounded point. The point is either mounted in a hand tool and pressure applied to the work that way. Or the tool is held in a fixture and the work is brought to bear against it with the needed pressure.

..and sometimes it's just used as a cosmetic bling.
The overlapping circle style has much more flash & shine to it. So it really took over the bulk of damascene or Jeweling work.
It really does the same thing as far as making slight depressions to allow oil to migrate on close fitting parts.
Most is done just for looks though.

The Vaver sight look like the correct one for the cut out. Good call on that.
Maybe the Vaver required the hump to be cut down when used on the '03 if they didn't offer anything with a stepped top bar for that feature.