Well, a bit of discovery since my original post. The "hood" I received from KEH was not a hood. It was a retaining ring bottom portion with attached clamp, but no hood attached to it. Odd this would have gotten through their system.
In the meantime I packed it up and sent it back for a refund.
Having taken care of that I re-started my search and located the correct hood in Mint condition from Igor Camera (Igor Reznik). He offers a fine selection of Leica and other collectibles at very decent prices and his rating system is quite accurate. The new hood just arrived and one feature stands out, its depth. It's actually deeper than the 50mm Elmar Hood.
I'll try to get a few photo's out soon.
Steve