As part of the letter GB I'm running I included a few other items in the associated products column above. Using the paint we matched for the grill and under the grill I touched up mine for taking pictures of the letters installed. This is nice to do if you have the discoloration I had and make it "picture perfect"

You can see what looks like wax, in the mesh and between the body and grill.
I wiled it down with acetone several times until it was actually taking off some of the over spray on the under side and some of the black. Let this flash off for about 30 min and shot it. I masked it below the edge of the deck lid to hide the seam. The engine deck lid welting will cover it.

The engine grill letters can be difficult to remove and are often unusable for re installation. If you gently use 2 screw drivers you can walk the old ones up the shaft of the old letter. This can be a little tedious.

After several rounds of wipes with the acetone I shot this too.

To reinstall the engine deck lid welting I notched the bottom. You can see this on the bottom I show trimmed for the side grill.

Tomorrow I will be showing how to attach the early rain tray.

What also works is using a mini cutoff wheel in the dremel and cutting beside the post. less chance of breaking off the post. But still tedious

Click to view attachment

Does the welting for the grills (engine lid, and two side grills) only go on the front edge?

Yes
It is only on the edge closest to the front of the car.