When you get a kit that is pre-inlet, look it over pretty well when you get it. I have bought two kits from a well known supplier, and the inletting was sloppy. I thought the first one was a fluke, but the one I am working on now, has a gap of around .025-.030 the full length of the barrel channel, oversize lock inlet plus a nasty machining gouge at the rear, and oversize entry thimble inlet. It is going to take a lot of filling to make it look good. All in all, very disappointed in this, considering the cost, but the customer said to go ahead and do the best I can with it.
If you are not an experienced builder, if you see these problems, I advise sending it back, and getting something you can work with.