complete beginner

hello again. i have a question about replacing my head light bulbs. My headlights basically suck. can see a thing with them so i was gonna replace them. i found some euro dezigns 8500k h.i.d xenon-krypton light bulbs and it says it is d.o.t approved. my question is if they are dot approved are they suppose to have letters dot on the bulb socket light my regular lights? would ask my bro since he bought them but hes away, so i turn to you guysfor help on this board.