Unknown desk cabinet

I found this piece of furniture and found it intreeging.

It's old, made of wood. It has very old hardware (vintage locks including the vintage keys) etc.

It's very plain with very little decorative detail.

I was told it's a cabinet desk. I'm also thinking it might be some old mail sorting station or something else.

All the doors have locks but operate with the same key.

Any info would be greatly appreciated!

Thanks!