Dave- On the D.VII the frame was cast aluminum, on the F.I/Dr.I it looks more like wood to me. Here is the best photo I have. Either way, it was probably painted olive green. Inside was a ZAK stamp and the date of inspection in pencil or grease pen covered by clear plexi or something similar like windscreen material.
Taz
Terry Phillips
Dr.I 198 17 WN 1916 Jasta 14 Ltn Werner Newly Delivered Ur.II Rear Transparency Detail.jpg