The sliding window nearest to the lower helm station on my 1979 MS1 must have been broken at some time in the past. Someone installed a smoke colored Plexi-glass replacement. I would like to do a proper repair by installing a grey tint tempered glass that more closely matches the color of the rest of the glass. I've located a place to buy the glass and they will cut it to size. Does anyone have knowledge of the procedure to remove this piece of glass from the window frame? Must I remove the entire aluminum frame in order to accomplish this repair? Thanks.