I've actually seen them start to rise here in CA as well. There's a couple 380s with 50-75k miles on them that are selling in the 20s around here. They are definitely clean examples, but those prices would've been unheard of a few years ago. I think that with most things, the CA cars always start to rise in value first since we have none of the rust issues and I think that's what we're seeing here.
On a related note, my father the eccentric Brit is in the process of buying his retirement home in the UK and moving back for good. However, his last order of business is to buy a Rolls Royce, probably of the Silver Spur II or III vintage, and take it with him. Apparently he has been speaking to a number of dealers over there and they're telling him he is better off buying a CA car and shipping it over because almost nothing of that vintage (similar to our 107s) remains without serious rust issues in the UK and those that do command astronomical prices.