Nice job Adam. I wish my first looked that good!
Fit issues will come with time and practice, as well a finish issues. I can see lines in the pen finish that go around the barrells. Be sure to sand with the grain of the wood when you are sanding with each grain of the sandpaper, or those lines will stay in the wood and the ca finish. That is a tip that has helped me along the way, and hopefully will help you as well.
E