For most of the woodcock hunting I've done, Cylinder and Cylinder would be about the right chokes. You could accomplish this yourself at no cost with a hacksaw, but it might not look too pretty. A gunsmith shouldn't charge too much for cutting it off, squaring up the cut and resetting the front bead. This assumes, of course, that the rib doesn't present too much of a problem. Also, if you wanted the barrels threaded for choke tubes, that's about $75 per barrel plus the cost of the tubes.