ALL over the counter Microwaves will have an EXTRA set of mount screws NOT part of the Installation instructions for the Microwave. The reason is simple. The Microwaves are built for HOME use and there is no movement or bumping/vibration force put on the mount plate. In an RV, the heavy Microwave will be subject to forces that will cause it to bounce up and down and if the RV OEM's did not install additional mount brackets or screws the Microwave will actually shear off the back wall metal mount plate and fall down. This is why under warranty, the Microwave warranty company will NOT remove the Microwave in an RV for warranty work. You either do it or the RV Dealer does it. They also will usually NOT remove in an RV if out of warranty and the Microwave needs repair. Doug