Man I love AT-AT threads... can share some research! The AT-AT seen in ROTJ has its side guns mounted on the wrong side. The left gun is on the right side and vice versa. This can be seen in the Chronicals and in stills from the DVD. The shield portion of the gun assembly should be on the lower part of the gun body as well as the larger portion of the gun should be on bottom as well to match all the ESB AT-ATs. Maybe when they were adding the lights they put the side guns on the wrong side as the details of the side guns are completley opposite as seen in ESB.
the best picture of the ROTJ ATAT is in the ATAT fold out fromt he Sculpting a Galaxy book. Shows the front clearly and in good light.
The ROTJ ATAT can also be seen in the classic pic of MR Lucas being surrounded by all the models from the movie. Best pic of that is in the ILM effects book. It's the ATAT to his front. It has dirty feet and has the backwards side guns are still mounted. This atat can also be seen in the From SW to Indy book page 50 lower left picture (with the green dirty feet located front right side of the three).
A couple castings and 2 hero ATATs have made the museum tours and from Ive seen the only one that matches the details seen in the screen cap is the same one MR looked at to reference from the archive. The one MR photographed was a casting of this version AT-AT. This same casting was on tour and was photographed. This version ATAT is what I call the M60 ATAT as it has a large M60 tank spotlights on the side guns and was on tour for a while was the only one without the second layer of deatil as indicated in the photo.
The hero version started to come apart in between cities and eventualy recieved a clean head without any side guns or any other detail except lower chin guns. Then it was seen without any chin guns.
This version was seen on the Art of Star Wars San Fransico and the Magic of the Myth. There are pics out there of this version.. I do think it was re detailed to represent the snow version for the tour.. if its not in someones office still detailed like the ROTJ version.
From what I was told the only AT-AT currenlty in the archieves is the cast version of the M60ATAT from what I'm lead to believe there is a hero one there but is in various stages of disrepair. No photos.
I have identified 3 hero stop motion ATATs and maybe the proto not used in filming
#1 Stripe 6 hit (detail streak stripe is centered upper visor and this ATAT has 6 hit marks on the hull. This version can be seen Chronicals page 168 and 171 snow with army guy.
#2 Spots (painted white spots or splotches on hull) can be seen Chronicals page 169 top picture forground.
#3 JonBerg ATAT can be seen lower right picture with Jon Berg Chronicals page 171. Has a clear even streaks of detail on the hull and a distinct grey panel ont he hull (is on tour was first photographed at the MAgic of the Myth 1998) since the neck has deteriated be yound repair and the head no longer can remain int he upright postion. Several photos of this version can be found on the net. The give away is the dark uniform streaks on the hull.
#4 M60ATAT Ive seen the hero model with a replacement head and a house cast of this version currenlty on tour. Picture can be seen in the SW to Indy book page 50 with correct side guns and hull markings. Cannot find any screen used captures showing the M60 spotlight style guns in use maybe this was the prototype Don B. mentioned. Possible the side guns were replaced for the photo in 1994. (notice some of the leg armature is missing from the upper and lower legs this can be seen on the hero version while it was on tour) Prototype version?
Hope that helps a bit...
Steve
