Nice.
But I'd be curious who made the thing and where it may have seen postal duty in its day.
I suspect it was a typical "retrofit" to a general store or similar establishment that had a designated area for post office business. In any event, it would require a considerable amount of floor space to install it today, not to mention the costs in shipping it to whoever wins the auction.
In case the link gets lost, here's a jpg image of the item:
