Looking at possibly acquiring a 3.8L 2015 Genesis with 45k miles on it. Anything I should look at or ask them when looking at the car?
I have no idea how to answer this question. I guess you would do the same thing you would do for any used vehicle . If an individual their answers are always be positive and could be fiction. If dealer have them show a Carfax type report ( Not always accurate but can show red flags ) . And as other people say have a mechanic inspect it for a fee .
You could check the public library to see if they have a subscription to Consumer Reports. If they do, you can look at their most recent annual owner survey to see how the 2015 fared. You can also buy a CR used car annual at a book store and check the 2015 results.