Question about 811 call before you dig

We are having some concrete poured Friday to widen our driveway, and the concrete company said it was our responsibility to call 811 and have them mark the utilities. Everyone has come out and left their paint and flags that was on the list I got from 811. We live in Harris county, unincorporated Spring. We have centerpoint for gas and electric. Centerpoint was listed twice on the 811 sheet, but they only left one light orange flag and paint. Is this all for them? Or will another guy come? We have a gate I need to leave open if the other centerpoint person still needs to mark.