Look in the FF build manual in library - it shows decorative roll or "show" bar and its mounting pieces. The "show" bar (if original option) isn't there for strength or reinforcing of the chassis - its just for looks. Most refer to them as show bars or head-ache bars. General opinion is they would do more damage than good in a real roll over. I actually think they look nice on a wide body - but not so much on the classic body. You'll have few holes in your fiberglass and carpet (big one in tonneau too) but fiberglass won't distort and crack when you remove it.
https://www.speedsterowners.com/library/FiberFabB/images/FiberFabB041.jpg