Gas Tank issue...

Hi, I was told by the prior owner that my Dart has a new gas tank. It looks like it does.

My problem is when I try to fill the tank with gas as it gets to the top and gas starts pouring out from under neither from the filler neck side. Then of course as I drive it leaking out. I can't fill the tank past 3/4. It literally feels like there is a huge hole at the top of the tank.

I'm thinking the prior owner didn't put the neck grommet in. Before I drop the tank I wanted to make sure I cover the basic bases for what it could be. The grommets look to be around $15. Is there anything else i should grab that would be on the possibility list? I'm dropping the tank at a friends shop so I'm trying to avoid dropping the tank twice.

Thank you for your help.