Be aware that the 375 Weatherby belt is .003 smaller than the 375 H&H and would have to be set back to clean up the chamber. the 375 RUM however has no belt and a body diameter of .550 and will clean up the chamber. The RUM is also .350 thousandths. longer and will clean up the throat and the lead.
If you want to re barrel any of the three will work with your bolt face.