That is all true, but there is nothing to keep FN from moving production of the 70's overseas just like the other Winchesters. I've not heard anything of this before now, and would be surprised if FN made such a move, but it is certainly possible.
My gut feeling is that someone was misquoted in the ad mentioned in the OP and all of this will prove to be false. But on the other hand FN's SC factory was built to make military rifles, not sporting arms. I could see the logic of keeping that factory for military production and moving the 70 to the same overseas factory where the other Winchesters are being built. I hope not, but it is feasable.