They do seem to be very similar cars but I don’t know if it will fit. The 62 cutlass is a side fill tank that enters at the bottom of the tank (at least I think it does, I have not seen an original tank). It seems as if most GM products from that time period were rear fill tanks. The few side fill tanks we have seen pictures of enter at the top of the tank and that is too close to the frame to work on my car.
I am in St. Louis MO so I could probably pick it up if it comes to that point. I’m hoping to get a measurement on the height of the tank soon and maybe get another tank to fit. If it turns out that your tank will fit I may be interested. Thanks for the offer.