I wouldn't bet on it. I've just returned back from Orlando where I hired a car with the silver option. After resisting the salesman's attempts to upgrade my car category the conversation went something like this:
Salesman: You need to return the car empty
Me: But isn't there the option of full:full?
Salesman: No the package you have is for return empty
Me: I don't think that's right
Salesman: It is
Me: (after fumbling around for booking confirmation) yes here it is, it says I have the option of returning empty
Salesman: Well its in the computer system, there's nothing I can do, sign here
Me: You mean this part on the form where it says I have accepted the pre-fuel option?
Salesman: No you're just signing to say you're picking up the car
Me: But that's not what it says
Salesman: Shrugging, its in the computer system
Me: Just give me the car, I'll sort it out when I'm back in England
Salesman: (getting irate) Well you can call my manager if you like, and he can sort it out and remove the option, but it will take some time

At this point I just gave in and accepted the wretched pre-fuel option, I had a tired and cranky family after a nine hour flight and we just wanted to get away. In the end I reckon I returned the car with about ten dollars worth of fuel in it. It still pisses me off, because the man behind the counter clearly lied to me in order to get his commission on the fuel sale. But for the sake of ten dollars what's the point in pursuing it.