You have a real nice looking 4" King Cobra! Congrat's on a great find!
I live near you in the San Francisco east bay area and I have an identical 4" King Cobra to yours that I had purchased approximately seven years ago at the old Contra Costa Collectible gun shop in Walnut Creek(Now closed)for $800. And this just shows how quickly the prices have risen on these King Cobras! I once had a 4" blue King Cobra but I made a mistake in selling this gun about 3 years ago!