How is the A-Pilar / Drip rail / Roof Panel put together

[D-n-Tyke]

So started to prep the upper A-Pillar repair area. I started by removing the seam sealer from the gutter of the drip rail. What I found under the seam sealer has me scratching my head a little. I can see how the A-Pillar section goes under the upper top windshield metal but what I didn't expect to see is it looks like there is another plate above the upper top windshield that kind of sandwiches the a-pillar lip between them. That "random" piece of metal looks to have rusted and started to pull away from the gutter, but still looks to be solidly connected to the gutter. Is that "random" piece normal to be there? I was planning on just grinding it pretty flat and then reapplying the seam sealer over it.