everyone needs instruction to get to the top level of shooting (im speaking competitively of course,its hard to measure top level of CCW skills)
does this have to be a structured class? nope, its can be as simple as making friends with someone you know who is really good and shooting with them, they will critique you and help you. Or take some videos of yourself and post them on a forum where you know the people (brian enos being my choice) and get their advice. obviously the video isnt idea but it does work. In fact, a local GM did just that 2 days ago their to get expert opinion on how to keep his shooting skills moving forward, and another local GM i know jumps at every chance he has to take courses from world class shooters.