If it was me - I would either totally ignore them and bolt them on with the valves lapped, new valve seals, springs to match you cam, or do them right. Right for me is a complete rebuild for performance. I would assume they will need guides, new performance valves, 5-angle cutter valve job, cut the spring seats and guides, etc. Ignore the milling aside from truing them up. If the 318 is a place holder and you have a plan for what's next, ignore them. If that plan includes reusing the heads on the new engine, go through them properly. Budget in my area for top quality work would need $1500 if they are all complete ready to bolt on. Less money and quality can be had.