Hi bangster. You are correct. I forgot that the 2006-2012 Fusion/MKZ lugnuts were a different hex size than the 2013+. Then there are the other size variables on the 2017+ Fusion Sport and MKZ 3.0T models.But I digress.
In fact, for use with my torque wrench, I have a 19mm socket for my 2007 MKZ, and a 21mm socket for my 2018 MKZ. But alas, brain fog kicked in and I forgot.
So if he wants to be able to use the factory lug wrench, the OP will need to look for 19mm hex size lug nuts, I believe that would be 3/4 in SAE sizing. But no one should take my word on that, so double check.
They can likely be found on the same Gorilla website, or even using McGard lugnuts. I'm old fashioned and find it is best to call the company and simply ask them to help you get the correct lug nuts for your particular car.
Or for people not sure, just go buy 20 chromed lug nuts (non-capped), at an AutoZone etc., where you can talk to someone and return them easily if they recommend and sell you the wrong size.
Thanks for catching my brain cloud.
I will also add this only backs up my belief (which I often state) not to take the word of Internet strangers, without verification. Even information given with good intentions can be incorrect.