I heard from a test only smog guy in the LA area when getting another car smogged.
Within 3-5 years all diesels will be tested to get regisration. It will be worse than gas engine tests where depending on the year of your truck you are aloud to meet a certain standard. Worse than out of state smoke tests... All trucks will need to meet current model year truck standards for NOX, CO, particulate, etc. Yes a 96 diesel will need to blow as clean as a 2005. Sounds stupid but I would not doubt that in California. Also, if you don't pass the state will offer a buy back program or you need to retrofit your engine to new specs. Sounds scary to me!