I bet the newer Lexus UX flares probably won't fit your older model just right. The design and mounting points could be different due to changes in the body shape or trim. I’d suggest checking with your dealer to be sure.
I will keep saying this, the Lexus UX is basically a lifted Corolla Hatchback. If you're buying it for prestige, don’t expect anyone to turn heads or be impressed, just get the Corolla Hatch. But if you genuinely like it, go for it and enjoy the ride.