DOT/MC on trailer? Trailer reg question.

As stated, is it required to have the DOT and or MC on a gooseneck. I'm a hotshot setup, Ram3500 with DOT and MC display on the power unit. I've seen some hotshots around with this info on the neck of their trailers and wondering if I'm missing something.

Trailer registration. I just got my tag today and the clerk told me that permanent tags are for 53 footers. I have a feeling she wasn't certain. She said my trailer weighing in at 4500 (not GVWR, which is 15k) didn't need it. Did I pay for the wrong thing? I do have an apportioned tag on my truck.

Thanks in advance.

 

Everything indicates the DOT number is to be displayed on power unit. I'm assuming because tractors just hook up different trailers all the time. Anyone can confirm that if I have my own trailer (2 car hauler) used for commercial purposes (interstate) the DOT isn't needed on the trailer? Getting started is hard ya'll, lol.

Thanks for your input.

 

Makes sense, lol. Appreciate your quick responses. Trying to get on the road quick and avoid getting pulled over for dumb things.

 

lol I have mine in a bag with the rest of my DOT junk lol, is that secured or does it really have to be bolted down. Man!!