Yes dui checkpoints are required to be announced before hand to make them legal.
If they are not announced beforehand then it's considered a violation of your rights to detain you while they do their DUI checks.
But I wouldn't worry about it. As long as you're not driving under the influence of drugs or alcohol then you have nothing to worry about if you go through a DUI check point.
You shouldn't be drinking and driving or doing drugs and driving anyway.