I think the Greco in your picture of the headstock is different from the Japanese Greco. I don't want to plagerise someone else's work so I will refer you to a Goya site :
http://goyaguitars.tripod.com/index1.htm#home
If you scroll to the bottom index and click "Goya History" you can see the association of Greco with Goya. This was in the 1960's. These Greco's were made in Europe. The Japanese brand arrived in the 70's.
If you go back to the index and open the "Greco Guitar Catalogs" the 1968 catalog I think on page 17? features a Greco 921 model ; the same one is found on the 1970 catalog page 4.
This Greco has the same headstock and pointy triangular truss rod cover as the one in your picture.