"Robert11" wrote:

Hello:

Saw some plywood sheets in a lumber yard which
I don't think I've ever seen before.

Wish I asked the fellow there for a type designation,
but neglected to.

They had one surface unbelievably smooth, and uniform; at least for any
plywood that I've ever seen.
A dark brown color.
Almost looked like a verneer.

MDO? Medium density overlay has exterior plywood, with heavy brown
kraft paper laminated on the outside. Very popular among sign painters,
and others that paint rather than stain.

You can get plywood with layers of anything you want, depending on how
much you are willing to pay.