[bungle]

hate to say it, but i'm guessing yes. it might be hard to get a clean weld with sealant on the other side. sure you can probably get away with it for a while but with vibrations and time, you're gonna probably have to do it anyway. better than discovering a fuel leak when your bike catches on fire. plus i think it will put your mind at ease if you did it right.
sorry about the tank, but at least its fixable.