Looks a lot like an old pre war (WW2) brass oiler cap - from some type of machinery. These were unscrewed, oil put into tube then cap replaced, rod in centre kept tube from blocking. I have seen and used similar ones. Nuggy
Its a brass insert. As far as the age is concerned its hard to tell. They are used in a number of applications from automotive to beverage equipment to communications and so on. They come in a bunch of different patterns and varietys. Hope Im not breaking any site rules but here is a random website I found that shows a bunch of stylles and gives some basic info. This picture shows one that looks very similar to yours.
Well it looks like that - except for; the general aged look, the rod in the middle, and the fact that is not drilled through, but both are brass and tubular.
A little research reveals that the rod in the centre gets rid of air bubbles that stop the oil running down inside the tube.