No, The magnetic north shifts overtime due to the rotation of liquid iron in the earth! So your answer would be No they are not always the same distance apart! Hope this helps :)
Pacific Ocean
Sharing a common border throughout its northern extent with the United States, Mexico is bounded to the west and south by the Pacific Ocean, to the east by the Gulf of Mexico and the Caribbean Sea, and to the southeast by Guatemala and Belize.
Hope it helps you
Radiometric dating should be what they use
