Thanks!! I am glad everyone is answering back. 
Here is a larger scan of the cel with a black 
background that the seller sent to me. I don't 
know about the shadows because in many anime 
videos lighting is very different on cels than 
they are in the actual VHS or DVD copies...usually 
the picture comes out darker..is this what u mean. 
And no it doesnt come with a sketch. I can't help 
but thinking it is real, I would think that if it 
was a promotional production cel it would have 
some sort of code or sequence number, would it 
not? Thanks again. Here is the pic:

http://www.phreak.co.uk/tanime/goddess.jpg