I'm in the same situation as you. I'm replacing the floor pan and portions of the inner rockers. The COUPE rockers are diiferent than VERT rockers. For starters, the vert panels are galvenized and much stronger. The inner rocker that you can get do not match 100%. The steel is good and thick but it does not have the recesses necessary to allow you to attach set braces to it. You would have to do some work arounds there. I'm going to use the panel to patch my original. My rust issues was caused by a rodent infestation. Panels were plugged with seat packing material. So it's basically rust holes to patch and the pinch welds require replacement. I opened up the rocker's inner walls and found more rodent nests.
If your inner and outer are rusted thru I would get new complete VERT rockers.
I have replacement inner & outer COUPE rockers and the inner rocker for VERT. There is no way that a coupe rocker will match up to a vert. I post a link to some shots of my car. Do you have some pics?
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________
