I have the gaskets but reused the old ones.
The exhaust covers are Gerry rigged as the rear attachment points are connected using wire,they are coming off in favor of truck stacks,when I will install new gaskets.
Same as me, working on the 36" mitered truck stacks, and have the used gaskets on the stock exhausts, till I replace with the replacements and new o-rings. That's why I mentioned exhaust leak, mine sound close to the same as yours.