Greetings Danny. I'm pleased that's another mystery solved. Mind boggling that Dorr was one of FIVE satellite fields for Caltsrom! I have to say the picture showing the Dorr Field sign doesn't make the place look very inviting! Danny, in the colour photo of the cadets in blue gathered around the tail of one of the Stearmans, you can just make out the number "4" on the aircraft, aft of the rear cockpit..
There are some more photo's, I'll put them up later.
Cheers
Michael