For most buyers of older bikes, having any faults at all - like a gas tank leak - is a reason not to buy. Can it be repaired, easily or not expensively ? Or is it new tank, or tap, time ?? Or just a gasket/seal ? This is the question buyers will be asking, after all.
I don't know what market you are in, but unless its considered a collectors model then you are looking at a relatively low price as an older commuter or low-end cruiser (where 'new' and 'bling' are everything ?).
It does look in very good condition though. Ebay sometimes sees such gems offered, sometimes at silly prices - but sometimes they sell. They charge a fee thou, note. Even the bike wreckers may well offer you a surprisingly high price, since they may have contacts they can on-sell it to - at a profit... Hopethishelps.