Once upon a time, one John Moses Browning made bold to patent the silly idea of holding grips on an auto pistol with screws. But when Mr. B's pistols, made by Colt's Patent etc., made the big time, lots of companies decided to make auto pistols. But they all had a lot of problems figuring out just how to get around Mr. B's patents, and lo and behold they produced some marvelous mechanisms, including grips that were held on by clips and clamps and latches and notches instead of screws.
Those ideas are all available for the taking as the patents have long expired.
Jim