Coupe back roll up window

[Gil Sissons]

Looking at a 1931 Modela A standard Coupe project
The owner has collected some additional parts that would go with the car.
One of the items is a back window roll up.
He says this is complete..... after cleanup ready to install. Needs glass.
Question is.... how hard is this project? Does this take special glass?
Input appreciated
Thank you
Gil. NoCal