I picked up a used Remington 1100 slug barrel with rifle sight bases on it. The front sight I replaced with a Fire Sights fiber optic, but the rear sight ramp is missing the "carriage" that slides on the dove tailed ramp. Williams Gun Sights has a replacement sight, but it does not come with a "carriage" to mount it to the dove tail. Does any know if where I can find this piece? I'm hiving a little trouble finding it.