I would be interested on the input of the resident playfield resto gurus on this......
Given its in a high ball travel area, I would think a decal may not be the best option, and being right in front of the flipper area you will see it...Is the machine a keeper?
The area looks as if it could be painted fairly easily....If you can get a scan of the area on a good machine and get some masks cutout, then airbrush?
Were the STTNG diamond plate? I guess it can be cleared over the top otherwise mylar would be a realistic option....