The only place I`ve ever seen texture on the under side of the trunk lid is in between the framing. the textured part is the underside of the top panel. Unlike on the end caps I do not believe this was intentional but rather a result of the molding process. As for the fiberglass end cap textured areas, I have had success, after great practice, using graining paper like comes in vinyl repair kits and polyester primer. The can buy large sheets of the graining paper or other options like silicone graining pads from https://vinylpro.com/collections/grain-texture-1. What I've done is mask off the edge and prep the part per instructions for the polyester primer so it adheres, it`s essentially spray-able body filler. With only the area you want to texturize exposed, apply a single coat of the polyester primer. The tricky part is when to use the graining paper, because of the complex curve in the corner it will not lay flat and will wrinkle. so you can't just lay it onto the wet poly ad let it harden, but if the poly is semi hardened you can press it into the soft poly doing the main area with a single larger piece then and work the corner carefully with smaller pieces so as not to make edges where the graining paper edge is. that's the hard part. And you have to use fiberglass mold release wax on the paper so it doesn't get stuck and pull the poly loose. That's available on Amazon from total boat. Like I said, its tricky, but can be done. I`ve never tried the silicon pads mainly because they are not quite big enough. I`ve also used this with good results repairing the interior fiberglass panels. When selecting the paper I like VP5 for 69 stiff and VP3 and W1 on the interior panels, but you can choose, remember the graining paper is reverse of what it makes, so what appears to be the peaks in the pic ends up as the valleys when done. practice,it took me a while and still doesn't always come out right on the first try. If you don't like it riht away while the poly is still semi soft you can usually scrape it off easily and use acetone to clean off any left behind, then try again bt keep in mind the poly hardens like any fiberglass resin based material so you have a limited working window not only with the parts but also to clean the spray gun out. Now if your not that picky and want an easy cheat, you could just mask and spray the polyester primer light dry passes to make a pseudo texture, but it won't have the vinyl look of the original. And if you put it on too wet it will flow out to just look like orange peel before it sets. Hope this helps. Bruce