Gas Tank Question?

bought a new tank for my 72 Demon from a tank company in Maryland. It seems to be a tight fit? Straps are not aligning with the indented grooves. Tank sits offset to the passenger side and almost toughing the inside of the frame rail while it has more space on the drivers side. I ordered a tank with the single vent tube coming out the front upper area. I am wondering if I have the wrong tank shipped to me? Is there an actual size difference between years or just emissions crap to deal with? Or maybe a poor repro?