Um, maybe it is just me, but the two models look nothing alike.
The only similarity is the large plate above the arms (which isn’t exactly a unique idea) and in the Gundum picture there are two vents on one side, essentially because they needed something “cool†to fill the space.
Adding two large plates over the arms of a character (large shoulder pads, basically) is not an original idea (at least not for the last few-thousand years), and when you do add them, you’re going to find a lot of empty space with a need for filling.
Circles aren’t exactly a unique shape and have been used for centuries for numerous things, among which filling space ranks highly.
Emerald WEAPON doesn’t even have actual arms, and Quebley doesn’t have big round feet, nor does he have a giant mouth in his stomach (area).
Both characters have a crest above the legs that connect them to the main body, but what robotic character doesn’t?
Not to mention the fact that the crests are not the same shape, size, proportion, or remote color, and from the back, they aren’t similar at all.
Rather than a case where one holds originality and another borrows from that originality, this is a case where both characters are equally unoriginal, with one of those unoriginal factors being the same (shoulder pads).
L. Spiro