Scott, wish our registration endeavors were as easy as yours; however, you gotta remember that there has been a ton of changes in the California emission laws since 04...in fact I don't even think there were any for diesel motor homes back then other than being exempt from smog testing if over 14,000 lbs. Even tho you registered your 04 in May of 2011, it still only had to conform to the regs of 04.
We have been in CA our entire life and changing now in this late of life just doesn't make sense for us. We spend our summers on the Oregon coast (Newport) and winters here in the warm and sunny California desert. Life is good except for a slight hic-up with the DMV every few years. :R
Ron