1979 cents are made of an alloy of .950 copper. No plating at all.
What are the the characteristics of this coin that make you believe it is plated? Same question regarding any errors you believe are there.
Many of the "errors" that novices find are actually post mint damage. A few, however, are genuine errors. A detailed narrative, with clear, sharp, and detailed images is extremely helpful if you are to get well considered comments.
Right now, based on the images provided, it appears you have a very dirty 1979 cent, possibly with some damage. There is really too much dirt and debris on the coin to tell.
Too late for more coffee. But there is always tomorrow.