Since you tagged your photo 'inkwell' I assume that the hole on top doesn't go through to the bottom and it is about that size. You might be right, a promotional item?
I have always thought this was an inkwell but when I showed it to some peeps from the bottle club no one could really agree on what they thought it was. I was of the same mind as you, I thought it was a promotional item or sample showing what kind of casting they can do. The family name of Levering goes back a very long way in the history of the United States. But so far I have not been able to find the company name in the Baltimore directory.
Just to add a couple more thoughts, if you had more than one of these they look as if they would be easily stackable, or nested together. And because of the thin casting their use wouldn't have been industrial.