Sunroof Finish Panel Question

Yes, it is #1 as you noted.
I described it as,

"The panel is a tin piece which is painted grey like the rest, and is rectangular, with two large rectangular holes if you will. You can see it in the first pic, the holes allow you to see the outer sunroof panel beyond with the black X, which is actually contact cement with a bit of the old insulation which used to be there. You can actually see some of the old tan material, like the one in your first pic where it is being touched."

Note that the one in the catalog is just rectangular with one big rectangular hole in the center, but all of the ones I have seen are like the one in the first pic I posted where there is a center strip of metal, which results in my description of the piece having two holes.

The panel rides/slides into the channels (catalog item 9) on either side.

Yes it does generally slide into the area of your arrows, but it is hard to see if it is where your red or blue arrow is located.

The panels are flimsy and often missing on cars, they are not reproduced, so you would have to find someone with a used one to sale. Chances are slim becuase they would likely have a complete assembly they are selling if any.

I see it as being easy to fabricate one, they are not anything special, other than obviously getting the dimensions right. It is not a precision fit item, as long as you are within 1/8" on the width so that it does not fall out of the channels. Can be made out of a standard piece of aluminum sheet from the Lowes, requiring nothing more than a saw and drill for some holes. You would then just use 3M spray on glue and cover with material of your choice from Walmart/Fabric Store. The material plus the panel thickness need to equate to a snug but loose enough fit to slide up and back in the channel.

As far as overlap, it needs to be big enough to cover the hole in your headliner front to back, the width of it side to side will be dictated by the fact it must ride in the channel and be wide enough not to fall out.

Also, someone else here on the board could help you out by taking a few pics of their sunroof from the interior, with the sunroof partially opened, and also take a dimension for you of the distance of the interior/exterior panel edges on the front edge. Finally in absense of dimensions to work with, the back end will be dictated by the fact you have to have adequate overlap inside to cover the headliner opening, and fact is the back side has the most leeway/tolerance when it comes to size.

You ask if when the headliner is installed does it overlap the perimeter of the sunroof a bit? Yes it does, as described above. Also, there is a depression on catalog item 4 that looks to be about 1/2-1" wide, which is likely to accommodate the added thickness of the interior panel on the front side. This would provide you the extent of the front edge.