Thick flange for my '77. I'm putting them on now. Actually I'm drilling out the broken exhaust studs right now. Not much fun.
Edit: The link of SSIs you have above don't look at all right to my untrained eye. I started another thread with as much detailed info. as I thought pertinent and added some pictures.
http://forums.pelicanparts.com/porsche-911-technical-forum/850698-77-ssis-conflicting-info.html#post8477291