Odd Cam Cover

A little honey hole I found has this for sale. Notice how long the dome is on the ends. He asked if I could help correctly identify it.

 

Side view?

KZ1000

Steve, or anyone else elaborate more. I have a 1978 Kz1000 obvious in my LTD B2, and a complete spare ‘78 1000. Neither have that style cover. They both have 2 rings/ribs between the cam cap bolt clearance and the dome. The one in question has only one ring/rib. 

 

Saw that on Ebay.
Listing says it's an early 77 1000 light weight cover.
Thought i'd seen it all but it's a first for me..

wrote:

Saw that on Ebay.
Listing says it's an early 77 1000 light weight cover.
Thought i'd seen it all but it's a first for me..

Every '77~'78 Kz1000 valve cover I ever picked up always weighed a heck of a lot more than the early Z1/Kz900 valve cover. 

Never heard of a 'lightweight" Kz1000 valve cover.

I don't remember the exact amount anymore, but the Z1/Kz900 engine covers including the valve cover weighed like 5 pounds less than the same set of Kz1000 engine covers!!!

That valve cover looks just like the '77/'78 Kz1000 valve cover to me.

 

They both have 2 rings/ribs between the cam cap bolt clearance and the dome.

seems like someone got carried away with the polishing and made that rib disappear.

I've never seen one like that before. 

It may have been an early design for the KZ1000 that never made it past testing stage. 

It doesn't appear to me to have been modified after it escaped from the factory.  

Thanks for the replies. It might just stay a mystery. If anyone else knows please chime in.

As Requested