Since the guard was brought up, I thought I'd chime in.
I believe that I told Tom that the early ones were engraved. For the Hummingbird, hand-engraved guards may have only been for the prototypes and custom work. I have not yet seen a production model 'Bird with one. I've been keeping my eye out for 1960 'Birds in particular, but each one that I've seen has the molded guard. Those are easily identified by their red swirl coloration. My grandfather did hand-engraving and inlay work on the early Doves, and the Epiphone Excellentes with the Eagle guard. I have even seen production Excellentes signed with his initials near the tree branch base.
Regarding the monochromatic coloring, I think that has to do with the paint colors aging and the way that the guitar is photographed. The white paint has yellowed, and the yellow has faded. From a distance in low light, the paint looks almost like the same color. When shining a bright light on it, you can see the difference. See the photos below: