Carb Number!

I just had a real quick question on carb numbers. Isn't the carb number the only thing you need to prove that parts like intakes are california smog legal? Because today I got pulled over by some cop who asked for my receipts/documents on my exhaust and intake...he even asked me to pop the hood so he could take a look at my intake.
He saw I had a carb number and that all my parts were street legal, so he didn't give me a ticket or anything, but before he let me go he said that I was suppose to have a certificate with me that goes with the carb number and he said I should go home and look for it. Now from my knowledge, all you need for proof is a carb number and when I bought my AEM cold air intake, it didn't come with any certificate...so I don't know what the hell kind of certificate he is talking about.
I think he just got pissed because he couldn't catch me for anything.