What to do with my gas tank?

Not to hijack, just a quick question. I just put a new tank in my 66 Sat, there was nothing there ( but PO had pulled tank to try and drain the rust LOL) So I didn't think to put anything there. (cause I didn't see anything) Is this a saftey issue, or just a vibration issue?

I dont know the exact reason. However...factory had a pad between the top of the tabk and body.