I have an SX myself, but the EX ones I saw here all had the gloss black also. Where are you from? I am in Vancouver, BC. But regardless, i am sure you could order one from Kia, or have it painted professionally in the gloss. I don't know if that helps.
The 2011 EX models all have glossy black trim but the 2010 EX models have flat black trim. Leroy, me and a few other members on here bought glossy black lower and upper grilles from a seller on eBay called automotiveapple. You'll have to search him and email him. He doesn't currently have any glossy black lower grilles posted on eBay though.
I'm not sure it would turn out as well as the OEM glossy black grille and it would probably be more expensive. The SX grill has a smooth texture and the EX grill is a little bit bumpy for a lack of a better word. I bought mine off eBay for around $50, I would guess a body shop would charge a little more than that to paint it.
Yeah mine is a 2010 sx, but in 2010 when i bought my car, the 2010 ex's in BC had the gloss, atleast at the dealership I bought from. But I agree, the paint option truthfully probably won't look as smooth and glossy. I would source out a gloss one like SubtleStyle advised.