The instructions look correct to me. However, because you've got two motors, when you wire the second motor the yellow wire should go to brush two and blue to brush one. The GG1 trucks are built identically so one motor has to run in the opposite direction of the other. Those motors draw a lot of amps when running, be sure the e-unit can handle the amperage. Even on a smooth rolling, well lubricated GG1, the engine can draw close to 4 amps which is usually the limit for some of these types of e-units. (VoE). There's not much room inside a GG1 and it doesn't look like that e-unit is going to fit. Can it be installed vertically between the two motors? You may want to get on the Lionel parts website, look for GG1's and observe how Lionel may have mounted the e-unit.
Steve, I presume the green wire should go to the brass tabs sticking out of the motors. In the third photo it's the brass tab visible between and to the right of the two blue cylindrical items ? The black wire would go to the frame ? I want to run on live catenary, so should the red wire go to the solder lugs meant for that purpose ?
I looked closely at the pics, kind of hard to describe when everything has black wires attached. Looks like it was wired to run in one direction. The tabs that are attached to the screws are for ground and that's about the only thing that can remain. The blue things are capacitors. One is attached to each brush, you've got a left brush and a right brush. Solder the appropriate colored wires, yellow or blue to these brushes. There is a center tab between the two brush tabs, that is where the green wire gets attached. BTW, remove the black wires from the two brush tabs and the middle tab.
You can attach the red wire to the tabs for the overhead pants. Some people will attach the red wire to both the roller pickups AND the pants, others will attached the red wire to one or the other but not both. It's up to you, depends on how you plan to run the gg1. Hope the pics help.