I'd leave the gun's chokes alone. It is a lot easier to "open up" chokes using different types of ammo (including "spreader loads") than it is to tighten them. Especially if the gun is to be used for trapshooting, before I did anything else with the gun, I would pattern the thing using good-quality trap loads. Unless I miss my guess, I suspect that, after this is done, you will most likely not have the heart to mess with this fine old gun's chokes.