You could save yourself a lot of money. Just go to a craft or hobby store find a pushpin or bead the size and color you want and glue or epoxy it on the rib. No one would know but you and would cost you less than $20. It’s what we did in the 70s.
Pretty easy job for any half decent machinist. The hardest part may be sourcing the bead. After that, it's find the spot you want to install it, drill, tap, Loctite and screw it in. 20 minutes.
The longest step will be getting it in the exact centre (laterally) of the rib. Most gunsmiths will have a little jig for this stage. If that's in their tool kit, 20 minutes should see the coffee being served.
When Lisa had the two barrels for her gun, our 'smith did them both inside a half hour.