Should be a standard plug in the back. My old SMB had foam on the sides and top to snug the microwave in place. Pretty sure the owner before me did that, but I don't know what SMB actually does to secure them in place.
2005 E350 Chateau - V10 - Agile Offroad 4x4
2012 CTS-V Wagon - For the baby...
On my 2004, the microwave was held in place by screwing into the plastic feet of the microwave, and a piece of cabinet covered in felt? that wedged between the top of the microwave and the cabinet above.