I found the pic below off the web. Not my car (unfortunately) but looks like a nice resto so hopefully the exhaust shroud is correct?
Some pics on the web look stamped like the one I posted. The firebird central shroud looks more "fabricated" to me, with sharper corners, etc. but I can't say which is "right" or maybe both are (more than one supplier to Pontiac, etc.)?
It will be interesting to see pics from 71455formula.
...