Just a note:
Screw choking a potential modest collector shotgun will diminish market value with the exception of Briley in my experience. Briley won't really add value, but tends not to diminish value.
Obviously one would have to have money to burn to screw choke a "bespoke" shotgun.
Is your Silverhawk the older (409?) unit or the newer unit (471?) with the selectable ejectors and such? I shot my first birds with the 20g former. Then bought it off my dad. It was choked full/full. I had no use for a full/full 20g so had Briley add chokes. My shotguns are for shooting, not collecting and choking made a shooter out of it.
Most barrels will accept Truchokes, but do measure OD as part of your decision. As I said above, I had one 12g that wouldn't accept Truchoke.