fuel tank welding question

hello!

I´m planning to weld a sump on to a fuel tank. But I want a new fuel tank to work on. So I found this fuel tank on ebay: [ame="http://www.ebay.com/itm/161197741283?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT"]New Gas Fuel Tank Barracuda Cuda 1966 1969 Made in Canada High Quality Tank | eBay[/ame]

But I do not know if I can weld on the tank due to ni-terne treatment. I´ve tried ask the seller but he doesn´t respond. So what do you guys think?
Thanks Daniel