What is a sure fire sign that the CUE unit was replaced on my car?

I think the dealership my car is at has been less than honest about work that is supposed to be done on my car. It's in for the CUE issue of the voice prompts resetting to "LONG". It's been there for 17 days now. I have a 2014 CTS loaner so it doesn't mother me too much. Anyway, when I talk to my adviser, I just get this feeling they haven't really done anything and that his answers to some of my questions just seem like he's not honest. For one he said, your car hasn't been sitting outside and I know for a fact it has. I drive right by the dealership everyday and can see it. Then after not getting any feedback for a week from them I asked if anything has even been done yet and he said that they tried to reset the CUE and then they replaced it. Just something about the way he said it and stumbled a bit leads me to believe they haven't. This morning I had to grab something out of the car I left in it, so I checked the CUE and all my favorites were still tagged correctly (I renamed them all) I realize that they could have just programmed them all back in, but that sure would seem like a waste of time since it has to be done manually and the new CUE (according to the adviser) does not work either. Had the new CUE worked properly I could see them reprogramming the favorites as a courtesy.

So what would be the best way to verify if it was done or not? Nav history? Would that still be there somehow if it was replaced? Any other ways to tell for sure if it was actually replaced. They still have my car, but I am going to pick it up today as I am having some paint work done this weekend. I have my phone paired and I also have songs tagged (so that XM will pop up and ask me to switch to that song) If the CUE was replaced surely those things would no longer work right?