[Milsurplus] BC-221 Cal Book "window" help needed

[jcoward5452 at aol.com]

Hi All,
  I have here a pretty nice BC-211-T, however the clear plastic window 
for the cal book compartment is gone.Anyone have any ideas on how to 
fab a new one and insert it?If I make it just short in one direction it 
should be easy to pop in a facsimile but to actually get it into all 4 
grooves may be a challenge.
  It had no spares in the spares compartment except the Bristol 
wrench(!) but instead had the original battery harness and battery 
retaining strap.One knob is incorrect; it has that Navy RBM look 
whereas the original was a simple round black knob with a white arrow 
across the surface.Any trades?
 Thanks,
             Jay KE6PPF