There going to be used in a full choked model 12 I don’t have the heart to open the choke it’s a solid rib.
Kinda went through the same thing.
I'd check to see if the S/N's on the barrel and action match.
If they do, I'd agree not to alter the gun....BUT....
if the numbers don't match, I'd send it to Briley in Houston.
To have the barrel bored and threaded for tubes is +/- $325. With that, you get three choke tubes of your choice.
I had a 1932 Remington "Sportsman" 16 gauge tubed by Briley. Shoots great! An old, fixed choke gun now has a new life.
Also, don't forget that choke tubes are all internal and not visible. They aren't like a PolyChoke or a Cutts.
....and YOU won't own the gun in the afterlife! 😉