You need to look for minor things that can be big things later. On mine the main issue was the trigger. First it was just a hair too thick for the slot in the trigger plate. The second issue with it was once installed it had no take up. At full **** you should have a bit of a wiggle to the trigger. This indicates the sere is fully engaged. Mine had none and I had to take maybe 1/16 of an inch off it to get it right. But just do NOT lop off 1/16 of an inch. Check it then remove maybe 1/64". Then check again and remove as needed. Keep it up until you have a bit of take up. I went with 1/8 inch at the trigger tip. Also had to remove a tiny bit of wood that was interfering with the action. Maybe a toothpicks width and 1/4 inch long.
And one a lot of people seem to have issues with, the last (inside) foot or so of the ramrod needs to be tapered. DO NOT BORE OUT THE HOLE! The kit includes a metal end piece for inside the stock. Taper the ramrod to fit in that. Then attach the piece to the ramrod.
I made a poor mans lathe for the tapering. I chucked the ramrod in a variable speed drill I had tied to the bench. I then supported the other end with a pillow block secured to the bench. Wrap masking tape around the rod where it fits the bearing in the pillow block. I then used a variety of rasps, sandpaper and such to taper the last foot down. Cheaper than buying the right tools.