[squidtone]

xkeots,
I get the feeling you're talking about the "inside" section of the rocker panel; the section that faces the frame of the car. I haven't done this repair, but I've seen some folks do it, but only when they are doing a floor pan replacement. It seems to me it would be a bear of a job working around the floor braces which are welded to the inner rocker. Even so, I don't think you'd have to disturb the outer rocker to replace the inner part.
But mostly I wanted to let you know that convertible rocker panel assemblies are more complicated than hardtop/sedans. I recently did repair work to my 67 convertible up by the thick sheet metal sandwich by the cowl/pillar/rocker area at the front of the body tub. I found that the A body convertible rocker panel assembly has a 10 or 12 gauge "C" shape steel stiffener inside the rocker going front to back. The hardtops/sedans do not have this piece.
If you do mess with the rockers, be aware that this C channel is welded to the top and bottom of the rocker with a million spot welds. Luckily, the inner rocker panel is not part of that C channel.
Good luck!
dave