A Galvatron with fixed shoulders should have the round indent for the pin at the back of the shoulders be in the top half of the rectangular gap for the mushroom peg. If it's the lowered shoulders, the pin will be at the bottom half of the rectangular gap. The proper assembly should also have the purple ring sandwiched between the shoulder halves be smooth all the way around. The misassembled one has some sculpted tech detail showing at the top of the shoulders.
Not 100% sure but the pic of Galvatron's back looks like he has the misassembled shoulders.
Fixed
Misassembled
(Mine got a bit dented when I fixed the shoulders)