exhaust questions

[IOWNATRUCK]

i bought a cherry bomb glasspack from summit to see if i like the sound and if not il probably go with a dynomax bullet, but its 8 inch for my 350 crate 84 c10 stepside and i know they claim that theyre reversible, but im not sure if its just the newest ones or all of them and i just wanted to see if anyone knew. cause if you look inside theres louvers and one side theyre open and the other side theyre closed so idk which side would go toward the inlet side if it even matters?
Thanks.