911 rear shelf mated to tunnel question

[drvfastliveslow]

I am currently replacing the rear shelf in my 72 911 from where your heels would be if seated in the back seat all the way to under the rear window. I have drilled most of the spot welds, but I am having trouble telling how the two pieces of metal are joined on the arch of the tunnel. See pic below. Any help would be welcome. Thanks
Lee

[Fishcop]

Lee, that area is fully seam welded, you'd need to grind the entire seam. If there's nothing wrong, I'd avoid grinding that seam and cut around the outside and butt weld the new panel in; or you could lap-weld that area as you can get to both sides to use a seam sealer.