In the jy's I go into, they often punch holes in the fuel tanks to make sure they are empty. Its a state safety regulation in some places. The only cars with intact fuel tanks are ones that have come into the yard very recently.
If you want to find a jy fuel tank, you should probably go in and talk to them, maybe leave a card with your name, ph # & what you want and are willing to pay for it. Even then, many places choose not to be bothered.