Hi roajeep, looks like laminated glass, the laminating film yellows with age.
Safer and easiest fix would be clear polycarbonate sheet, also good for “glass” for dashboard instruments. Craft shop would have some in small sheets eg Hobbycraft.
There was a repro version of the flying goggles by Stadium, might be same size laminated glass. Used a pair on my series 1 when I had the screen down.
Peter