Just an update. The crisis has been averted and they have agreed to do the filter change for free as it should be. I don't think these guys meant any malice. I just don't think they get too many vettes in for service and didn't have any idea there was a complimentary DCT filter change. GM should do a better job communicating these things to the dealers.
Now they get to use your car for Maintenance Training. Good luck Papa lol...