I understand that they are 75% copper but this one is 100% copper there supposed to have a clad layer of nickle on outside I'm going to Mic it I'll post thickness
Nickels are not clad - none of them. The alloy is 75% copper and 25% nickel throughout the coin. If you weigh it, I will bet you get about 4.9 grams - indicating it is the proper alloy and thickness. The color you see is just contamination.
Nickels when exposed to the elements often tone a copper color. I have found many of them metal detecting that show this coloration.