Bill Brophy was a close friend and never expressed that point of view to me. The reason he made several identification mistakes is he (and everybody else at the time) used a government publication which was not designed to identify parts markings.I have heard Brophy had no intention of including the M1903-A3 in his book. Only did so at the urging of his friends. Problem was he disliked the 03-A3.
You can read the whole explanation on my page of myths:
Bill Ricca's Page of Myths