Yeah, there is a very detailed explanation in this thread somewhere and I studied it thoroughly like I was studying for an exam when I did my CA registration. Basically, to get a "kit car" registered in CA, you have to put it down as Special Construction or "SPCNS" on the title as the manufacturer, being that presumably you built it yourself or paid someone to do it, who is not a car factory. Being that it's not a factory built car, it then is exempt from certain things like smog and 3rd brake light requirements of factory cars.
But they limit the number to 500 SPCNS titles per year for whatever reason. Guess they don't want the streets to be running over with tons and tons of SPCNS cars in CA? So, as each SPCNS application came in, they assigned a sequence number start at 1 and going to 500. When it hit 500, they stop SPCNS registrations for the year.
In any event, it used to be that if you didn't go to the DMV bright and early on Jan. 1 or whatever first day they opened, you didn't get your sequence number and have to wait another year because they would assign 500 within that morning. Now, guess the tide slowed down, and in 2012, I got my number in October, and it was in the 300's and Tiger got #262 in November, 2014.
Nothing clever to see here!!