Was your plate obstructed at the time the police pulled you over or not? I've cleaned the plate on my car and had it obscured by the time I reach the end of my driveway.
The most probable answer to your question is no. Unless you have proof it wasn't obscured at the time of the stop ya got nothin'
i suspect the obscured plate was a simple basis to stop you as there were likely to be other signs of your intoxicated condition that gave them reason to have a simple valid reason to stop you.

