Got an in-stock notification for threaded compact barrels from CZ-USA on 4/26/21, looks like they are out of stock again, I can't remember how long I was on the notification list, at least 14 months.
In my experience no fitting was required on my 3 P01 Omega's and 1 P01 steel frame when switching out the stock barrel with a threaded barrel, your mileage may vary obviously.