You're not going to find that....DOT does not "approve" anything. DOT has a set of standards and products are supposed to comply with them. AKA, DOT compliance is the technically correct term. So you're wanting anything that is DOT compliant, if you care about it.So out of curiosity I did the search for the DOT approval of these lights and so far have found squat on NHTSA. I’ll keep looking.
Legally not many places care about DOT compliance. I for one though find that light output is most usable and least intrusive to others when it's DOT compliant, so I always only buy items that are compliant. Those super bright headlights that blind everyone on the road, are not compliant. I don't want to be that guy.