Remington Police guns didn't have vent ribs.
Sounds like a sporting barrel that may have been cut down.
The Remington Police and Wingmaster barrels have threaded bead sights that screw on and off.
The Express barrels have pressed in beads.
It's "possible" to remove a Remington rib, but it's not easy.
The ribs are brazed on with a high temp brazing compound.
You have two choices of removal.
1. Is to start at one end and heat each pillar that joins the rib to the barrel to a red heat until the braze melts, then bend the rib up slightly so it's not in contact with the barrel, then move to the next pillar. Continue until the rib is removed.
This will leave brazing compound on the spots that will need to be ground or filed off flush with the barrel.
The down side here is a possibility of barrel damage caused by the uneven spot heating.
2. Cut the rib off.
To do this use a hacksaw to cut each pillar as close to the barrel as possible, then grind or file off the remaining parts of the pillars.
This takes time and effort, and you have to be careful not to cut the barrel.
Options:
Buy a new barrel like you want and sell the old one.
Have a gunsmith drill and remove the broken bead sight shaft and install a new fiber optic sight. This is fairly easy for any gunsmith and shouldn't cost much.
Of the choices, this is probably the best.