Spare part. Necessary?

[VW Splitter]

Putting back together my T435. Almost got it back together and got this one spare part left over. What is it? Heat shield maybe. How important is it? Take it back apart and install it? Or let it ride?

 

[RedneckChainsawRepair]

Looks like part 7 gasket.

 

[VW Splitter]

Thanks. A picture is worth a thousand words. Didn’t have to take much apart to get it back in. I believe it is a heat shield between the exhaust and the fuel tank.