Razpula is the wheellock authority but I will add my thoughts FWIW.
Most originals have smoothbored barrels of large calibre...like fowler barrels. They are thin at the muzzle making the dagg handle very quickly. Remember, the favoured man's weapon of the era was the rapier, which accounts for the grip shape, and being light and fast at the muzzle was the fashion.
My pistol has a rifled .40 cal barrel that started out life in Les Bauska's shop. It has a 48" twist, but I suspect that because of its length, shoots remarkably well. I turned it round and swamped for two thirds of its length, and filed the octagon to blend at the wedding band. That gives the breech a nice chubby dimension, and makes the muzzle fine.
I'm of the opinion that the pistol should be finished as is, or you could turn the barrel to a nicer profile, taking away a lot of the muzzle weight. It would mean a new stock though...no biggy. It's a pretty decent looking lock, by the way. A great buy.