Possible mezuzah INSIDE the front door glass trim?

I was looking at my front door this morning and noticed a small piece of paper sticking out of the trim around the glass. Pulled it out and there was Hebrew written on it.

I somewhat hastily pushed it back in behind the trim and so I don’t have a picture of it before I disturbed it or what the writing was, but you can see where it’s stuck in the picture. Would it have been common to put in some sort of blessing or a mezuzah inside the trim when you’re glazing the glass into a door like this? House is old, over 125 years, so it could be a bygone tradition.