Best bet is to have it examined by a good gunsmith.
This project should be probable.I would have a competent gunsmith give you a quote for threading the barrel to except the Invector plus choke system.
The Invector, or "Standard Invector" system" was introduced in 1983. A few years later, the Invector-Plus chokes were introduced to fit the new back-bored shotgun barrels. These two choke systems will not interchange. If you have screw-in chokes in your shotgun barrel, the kind of system you have will be stamped on the barrel near the receiver. You must use the proper choke system for your shotgun.
No, Invector chokes will not fit the Browning Medalist shotgun. The Medalist typically uses fixed chokes that are integral to the barrel, while Invector chokes are designed for Browning shotguns with removable choke systems. It's important to check the specific model and choke compatibility for your shotgun.
Browning made choke tubes.
Go to Browning.com and type "Invector Choke" in the search function.
I don't think there is an invector plus model. Invector Plus is the choke system Browning uses on newer shotguns.
You will have to call Browning to find out.
Either Invector or Invector+ depending on how it left the factory.
The Invector Plus choke tubes were first introduced in the 1989 Browning Catalog which was published in October 1988. Keep in mind that the Invector was already standard on most shotguns and the Invector Plus was slowing being made available to many models. The Invector Plus choke tube system was available first on BT-99 models and then the BPS and high grade doubles.
To change the choke of the shot
Yes. Briley or some other company will have to do the modification.
Browning did not make an Invector model. That is the type choke system of the shotgun.