I picked up this Benjamin 392P on the used list at AOA. It came with this knurled bolt. Being a lefty, I prefer it over the traditional right leveraged bolts. I can’t seem to find one on the market anywhere. I doubt it’s custom made because I have seen these on other Benjamin 397/392’s. I have other‘s that I would like to change over. The knob is larger than the knob on the Benjamin pistol. Any help would be greatly appreciated.