The building has only been painted twice since its construction in 1856-7. The first time was when it was first built and then again in 1865. After this point the building was periodically "oiled". With what kind of oil I am not sure of but there is a lot of evidence of it on the first floor sash and glass.
So the result is what you see today. Here is a current photo from a previous post.
This photo shows what kinds of problems that I have run across with these first batch of sash. The first thing I noticed was the variety of glazing putties that had been used over the years. Only one of the types was every painted, the first. Every subsequent re-glaze was not painted and all of it has cracked. Every type also showed how proficient or lack of proficiency the craftsman was at the application.
The second problem that I have run into is that a lot of the muntin tongues have been either worn completely away or have been scalped off so a larger piece of glass can be fit into the opening.