How old is this Eagle three lever lock?

[xAMMOx]

I found an old lock made by the Eagle Lock Co., Terryville CT. I'm assuming it's brass and am curious to know approximately what year it might have been made. I've been scouring the internet for some kind of information about it but am striking out, the local library doesn't have any good books, and I can't afford to buy a book just to determine its age. Can anyone shed some light on this for me? Thanks!