I would contact your local government office that deals with rentals. It seems in California, you folks have laws for everything and I remember reading something about parking spaces being required in certain municipalities.

If there is no government requirement, without the parking on your contract, you have very little claim to the parking to be included with your unit. Without a contract, it would be a gratuitous use and as such, could be altered at the owners desire.

Yes, you can get folks to say those 2 spots were said to be yours but with no claim by contract, there is nothing preventing the owner from changing their mind about them.