how did you guys manage to unpack those .bin files for the Endurance?
We didn't unpack any bin files. It seems they recently changed their formats to .bin, possibly to prevent further ripping.
Is there any chance of you releasing the original .obj models?
Just releasing in the proprietary format of "sm" is skirting the lines of copyright infringement. Openly sharing the model files might not be a good idea. I would prefer to keep things as they are and if someone from within the modding community of SE, Orbiter, KSP, or any other game needs the files they can private message me about it.
I have given single OBJs to a couple people to work with or use for scaling on their own projects. If you need specific OBJs for a project or just to learn from them send me a private message and I am sure we can figure something out.