I wouldn't worry about that too much. Have you ever heard of that kind of thing getting someone in trouble? Of course not because that stuff doesn't happen, or virtually never happens. If you find yourself in that situation (prosecuted for what you believed to be justified self defense), that minor an issue will not make any difference, if it is brought up at all, which it probably won't be.
Besides, all your lawyer has to do if the prosecutor start looking down that path is subpoena (or just hint he will) the local precincts armorer who will either have to perjure himself or admit he has smoothed parts on guns and replaced springs himself. That will get that whole thing shot down in a no time and it will never be mentioned in court.