But the odd thing is that my first series model, with half-moon trigger guard and no serial number, which must surely predate yours, has a vulcanite grip. I would have assumed that when Frank Clarke handed over the pistol to Accles and Shelvoke for bulk manufacture, the use of horn grips would have been abandoned at that stage, and probably even well before. It looks like there may have been some random use of old stock grips from time to time, perhaps when supplies of the vulcanite grips were short.