Almost sounds like the " civilian " glazing hole was filled with a " military " frame and slider glass ( still using the ( 14 ) bolt installation ? If so, I would think an original or repop exterior bezel and rubber gasket may work in place of the one you have. The rubber gasket can be cut to length, butt jointed, and glued with a " superglue " type product ( Steeles Rubber can give you the glue spec. )
