Sounds interesting. Only one low res engine bay pic here, but Moss Motors has detailed diagrams of the bays of the newer B's in their FREE catalogs showing alll of the smog stuff.
I agree that a car stored for that long will require some mechanical re-furb to get it back into running condition - could be considerable.
For example, my recently purchased 1979 B had been nicely restored cosmetically, but had not been driven much in recent years, and cost me about $2000 in mechanical repairs to get it running well again. Included was an exhaust valve replacement (four valves) plus a head re-surfacing and gasket.
I don't know what smog requirements your state has, but in California the later B's (1976 and up) are still required to pass smog. This can also involve some expense, too, re-fitting the car with newer cat. converters.
Also, on these cars, your ability to convert them to better carbueration systems (e.g. twin SU's) is limited, again because of the smog requirements.
I'd be inclined to 1.) Negotiate a price for it which takes all of this into account, or 2.) as has been suggested, look for another car (perhaps with more milage) with documented repairs to it.
Overall, I think little use is worse for a car than the opposite plus regular maintenance...
