If it has rust that is in the upper panels like that in the pic, chances are that the whole thing is gonna disentagrate when put infront of a sand blaster.
On top of that, there are MANY missing parts on the outside.
In My Opinion: I agree with what Kevin said above.
Unless you are very skilled at body work and you have a great shop with all the tools to do it and you have another exact copy pump to take parts from, this pump would be a bad one to do your first pump with. I don't mean to discourage you at all but there are better condition pumps out there to do your first one with. I only share this with you to save you gobs of time and heartache and I'm not trying to be rude to your friend or his stuff.
I personally would be hard pressed to pay more than $100 for this one because it might not even make a good parts pump because of the rust.
Dave(509)847-5893 LOOKING-4:WELDING SIGNS,Charter/Finance/PulOil/Trulite/TruTest-Oil,FREEDOM cans,True's gas CORALINE/RAINBOW,FLYING A,Wa/Or/Id Chief!