Some counties in Calif. require you to 'declare' you have a weapon when you are stopped... for anything. My county is like that.
Could he have not known the law? VERY possible.... no two states are the same... and beyond that counties can differ as well. So - he's pulled over for speeding... no reason to search the car.... he automatically, (as you say), says "I'm carrying a weapon officer".... that may be required in Georgia (is that where he's from?)..... officer asks, " you have a CCW?"...... Kendricks doesn't present one, or DOES but it's from Georgia and not valid in Calif. (that would surprise me since he has some history of a firearm infraction in the past? I know nothing about that.. BUT.... NOW there is reason to search.
But to me the point is: They had to have a reason to search his car. And that he's charged for carrying illegally but nothing about why they searched in the first place is odd. - JamesJM