[lal Naja]

I believe the Butler body has the rollbar receiving sockets already welded in place. In the trunk you will see one upright tube that is welded to a horizontal tube that is glassed into the cockpit bulkhead. This is the right upright socket for the rolbar hoop and goes trough the trunk floor and bolts to the chassis crossmember just to the left of where the differential bolts to it.

The left socket for the left upright of the rollbar hoop is hidden and boxed in with a fiberglass shroud. This socket bolts to the left chassis frame and you will see the bolting bracket inside the rear left wheel arch.

There is no pre-fit mounting location for the rear extending back stay tube. You have to cut through the trunk floor at the correct location and drill two 3/8" bolt holes into the chassis to secure the rollbar back stay.

Click on my facebook link here and go to my Albums, look at the album on how I built my Butler Cobra. I have lots of detail step-by-step photos of how I installed my rollbar.

When I bought my Cobra from Ron Butler I ordered it without the rollbar. 25 years later I wanted to install one and I called Ron and he had the rollbar (hoop & back stay) I purchased it, carefully marked where the holes needed to be, drilled the three holes in the body, cut the hole in the trunk floor and fitted everything perfectly and got the height of the hoop correct to fit under the Butler Hard-top/roof.

Call Ron, he very likely has the rollbar components.