Yep
just cuz someone makes something doesn't mean you need it. The factory might even have used them,(?)
but I never took one off a factory set up.
My cars are all older then that page (70&up).
I've been doing this since these cars were only 5 to 10 years old.

You my need them, all I am saying is I never have.
Get them on straight and they don't leak.

I have seen alot heat risers leak and folks thought it was at the pipe.