Using epoxy It would also allow the production line to only make one model to sit on the shelf and then epoxy the ones going to Customer X when they need to go

Using epoxy It would also allow the production line to only make one model to sit on the shelf and then epoxy the ones going to Customer X when they need to go out to them. If you cut the traces then you'd have to make 2 different types and track them, and really make sure none of the cut traces ones make it to Customer X.