We're talking about a Mossberg.
If you want choke tubes, why not buy a barrel that was cut for tubes at the factory?
How expensive is a Mossberg barrel?
This business of having a "gunsmith" auger-out a shotgun barrel for choke tubes does not always go well. Then you're STILL buying a new barrel. Ask me how I know!
If you don't want to keep the old barrel, you can sell it to recoup some of the cost of your new barrel.