I have a NEF 12 ga and am wanting a slug barrel for it. My serial # starts with a "N" so I can get a 20 ga with rail mount fitted to it or a 12 ga with sights....Question. can the 12 ga be drilled and tapped for a scope. I am assuming that since they dont offer a 12 ga with rail mount for this receiver that that means it is too thin??,,,,,what should i do. dummie me sold sb2 receiver recently that was on youth 243...oh well.