I think it's more the older car. I have 2 cars, one in Beta and one in public release, and the interface/fonts/etc are all the same. There's no noticeable difference outside of the Beta visualizations.
I would hope this isn't the case since mine is a 2018 Model 3 and the screen looks significantly better, whereas the service loaner is a 2019 Model 3 and the fonts look like they were designed by Play-Skool employees, or for people with reading issues. Very overly rounded, road sign icons are all much larger, the regen/power bar thickness is much larger on the 2019, etc. Basically it looks like it was designed for children just learning to read and know their shapes.