Yes, my great nephew, a red headed Norwegian Lutheran and now a college freshman, has been on the no fly list since he was about 5 years old. Have no idea how he got on there, or who his name-sake is, but it’s made it miserable for him. So... he can’t own a gun?
I’ve heard too, that if you are on a watch list, you are not able to find out why you are on the list. There are no specific criteria, and no explanations given. You will run into brick walls if you try to determine why you are on the list and whether a mistake was made putting you on the list.