Look inside at the Brace that runs Horizontal at the top part of the cowl. Even though the exterior is not punched out for cowl lights, the brace has a hole for mounting the cowl lights. I would find 30-31 cowl with the hole in it, and no light, and make a your own template. Tracing the upper outside corner, on paper, cutting it out with a pair of scissors, until it fit the corner, then trace the Hole and don't cut it out, to find center, to drill out your cowl. Measure the hole for correct size to finish drilling. I would use a Hole saw.