On our 1999 350 the wooden faceplate around the microwave just pulls off, held on by hidden clips. We just pulled off the surround, unscrewed the old MW, slipped in a new stainless one, plugged it in, and snapped the faceplate back on. Easy to center the new MW by clipping the wooden surround on and off to adjust the placement of the MW. EASIEST job yet on a boat!
Bob