The video had the two fuselages assembled on stands, but there were no cockpits. Perhaps blue/gray (Gold 2) cockpit has yet to joined with the fuselage in this pic, while TIE Killer (Gold Leader) was already finished at this point? Red 3 hero and Red 6 pyro are also absent. Built before the rest and unavailable for the photo op, or built afterwards?
(Referring to the video "5757" ILM documentary by David Berry) - yes at 3:00 you see some hero Y-wings being built, The one closest to the camera has a droid and the "U" shaped tubing on the back, making it "Gold Leader" ("TIE Killer").
(Referring to the famous table picture) Based on the latest input, we could speculate that Red 6 was already destroyed and (more controversial) that the Red 3 hero was not completed yet, or simply was mounted in the studio for filming its famous "rolling" shots. Since Red 4, 10, and 12 still existed, I think it's fair to say that the many "table pictures" were taken before they were made aware that they were way behind shooting schedule and before things became much more "urgent".
I can only add that the thin blue stripe running along the edge of the
decapitated Y-Wing cockpit matches either
Gold Leader (pyro, since the Gold Leader model is already in the picture, complete) or
Gold Two, as both had that thin stripe.
P.S. - Thank you
kk1 for the link to that movie - excellent!
P.P.S. - has anyone ever identified the person working on Red 6 in the bonus DVD? He comes out in several other shots and must have been hired later, but he's not one of the earlier seven model builders (McCune, Beasley, Erland, Gawley, Huston, Jones, Peterson). Could that be James Mallasch? I really admire the ILM crew and would like to know who he was since I can't find him credited anywhere . . .