I would look on the light lens and check for the word DOT stamped into the lens. This means the light is DOT approved... Some places may require your running lights to be DOT approved. I almost think here in VA they will require DOT approved types for all of the trailer SAFETY lights... Especially the ones visible from the rear of the trailer... DMV State Safety Inspection places around here really watch for those sort of things...
I know I added some of those back-up lights from an ebay source below the rear square bumper on one of my trailers and had to physically remove them before the DMV would pass my State Inspection. They said if the unapproved back-up lights were mounted on the side of the trailer in the rear no problem haha...
Roy Ken