I am Canadian Coast Guard Auxiliary which is something completely different to the USCG regs. Canadian CG and CGA is mainly marine search & rescue with our air force providing air search. Our CG may also do environmental research and such. Neither of us do law enforcement as neither of us are armed forces. In the US, you are military, with SAR (Search & Rescue) being only part of USCG's mission. The US lives up to the name of Coast Guard with many armed, there is even discussion of re-arming on the US side of the Great Lakes. The last time our nations were armed here was with cannons which incidentally is making negotiations quite difficult as to what modern weapons are acceptable. On the Canadian side only our Police are armed (don't even think of invading as I do carry a knife or 2 ). Having said this the United States Coast Guard and USCG Auxiliary can be justifiably proud of their training, efforts and dedication of duty. They are world leaders in SAR in addition to all the other duties they are asked to do. They may be in the shadows of the four more recognized branches of service but in today's climate they are no less as important. Should you answer this calling, serve well brother, you will be making a difference.
The USCG does indeed have a tartan but that may be only reserved for their pipe band, although here is an interesting link about converting a CG uniform tunic to a kilt jacket.
Also search the Show Me Your Ride thread as a couple of former Coasties have shown their former vessels.