Congratulations to Johnny for finding Dinosaur #57!
Here's the hunt in Johnny's words:
As soon as I got the tweet, I sprang into action. Went online to get a good look at the clue. I knew it was in Alameda so I checked Google maps for Post Offices. I thought this was perfect since I had something to mail.
Drove from SF to downtown Alameda. Parked the car. I started looking for clues (stickers) to point me in the right direction but didn't see any. Looked at the picture again and walked to where the dinosaur was.
Must be in the bushes.
Found it! This one was way too easy.
Then I walked in to mail my letter and discovered it was no longer a Post Office. Doh!