That's the one I was going to get before ultimately going with the Bandera. $50 is a good price as long as it is just surface rust. But I see it doesn't have the warming plate over the firebox which is handy.
Here is a recent thread on that smoker:
or just search for "New Braunfels Black Diamond" or "New Braunfels Hondo"
The NB Hondo / Black Diamond is still considered a COS, but it is a quality COS with thicker metal than most of the newer COS.. and it can be modded to work well.