Beautiful "knock down" hutch

We recently purchased this hutch and was told that it was referred to as a "knock down" hutch. There are three rods on each side of this piece that run thru the hutch and has a wing-nut on the back.
We only know that it came out of Maryland, could anyone please tell us if this is what it was called and approx. when it would have been made, etc... It is a beautiful piece and we love it, thanks