Yeah there is a tag lamp fixture made for truck step bumpers that fits the hole but... It's lens is half shaded so all the light goes toward the license plate. It doesn't serve just right in this vert application. Better than nothing. I think its this one. Measure the hole before ordering.
License Plate Tag Light 12V 1.1/4 Insert Round Chrome Step bumper | eBay
It doesn't get the required chassis ground when mounted in plastic so one would need to solder on a ground wire.
