Fuel tank replacement - plastic shield/cover?

[dh1989]

I'm preparing to replace the 34 gal tank on my 95 GMC K1500 long bed. I have a new tank, pump/sender unit, lines, filler hose, and straps which will be going in this week. I noticed that the old tank is inside some sort of plastic cover at the bottom. I remember reading somewhere that this plastic cover traps road salt and leads to the tank rusting out. I'm replacing the tank for exactly this reason, it is rusted and leaking.

Is it advisable to reuse that plastic cover sandwiched between the straps and the tank, or should I just bolt the tank up without the cover? I just finished coating the entire new steel tank and straps in 3 coats of Rustoleum so I'm hoping to keep the new tank rust free as long as I can.

Thanks.