Mounting plates for Leopold DPP

Apologies if if someone has asked this (I wasn't able to find anything relevant but I'm a moron) but I could use some help. I recently made the mistake of buying a new 509T from Bass Pro that already had the Viper dot mounted. The scumbag behind the counter assured me that all plates needed to mount any other dot were included but they were not. Other than Midwest Gun Works, can anyone recommend or suggest a place I can order the mounting plates and screws from? I've had zero success locating them. The Viper dot is ok but I really want to use my DPP with this pistol. Any help would be greatly appreciated. Thanks

CY