Hmmm, I would say it would depend on how it looks after. It is really hard to visualize how the end product will be, when you are pulling the collar from a different kit.
Is your intent to cut off the already existing collar from your kit and replacing it with another?
If that’s the case, are they the same files or two different designs? I would need so see how it fits into the backpiece. Another thing to consider is how it fits into the front? Width, length, angle of drop will all play a part.