How do 63 Valiant gas tanks mount?

So, when I got Mabel (63 Valiant convertible), tank had dropped, just one strap on it, and bungeed to hold it on. I bought new strap, and it came as a set of two, and the listing for hangar bolts (that I'll order soon) on Year One for it say 'set of two'.

The slot and hangar hole is on the inside of the frame on driver's side, but outside on passenger side?

I saw on Jim K's 63 Dart build, looked like just one strap? I've got DSM ordered, but till it gets here, any help would be appreciated!