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Starting in 2001, a sticker under the hood included something like "This vehicle is smog-legal in 50 states including California." Previous years had a sticker with the same statement except for the part about California.
But to answer your question, I'm fairly certain that there are no differences between California's and other states' C5s. They were all made in Bowling Green to the same specs.
My C5 was initially delivered to Capital Chev. in Montgomery, Alabama. It was then trucked to my driveway with all of 3 miles on the odometer. The DMV did have to verify that the emissions sticker was there under the hood.