Window screens on D&RG Cabooses *LINK*

Question: were windows in D&RG cabooses normally fixed ? That had been my assumption given inspections of 0503, 0524, and 0578. However, it was brought to my attention that a picture of 0579 immediately before scrapping in November 1951, clearly shows a ripped screen on one of the lower windows. Obviously the cupola side windows always opened, but I can imagine that on a hot day it wasn't real fun to ride in one of these unless the train was going fast to keep a nice breeze through the doors.
Maybe this was done during the filming of "Denver and Rio Grande". Wouldn't want the actors to get hot. Of course without screens on all the windows and doors, why bother ?
This is a very timely find as we were about to install fixed windows in 0579. If we knew they were hinged or removable we might change our plans