Both sides had Merchant "Privateer" Mariners in their employ. Historical documents show more Continental records than British or Loyalist, but they existed. And we are endeavoring to piece together what life was like for both sides of that same coin.
Is there a difference? Yes... Depending upon what side you are on, your interperetation of the rules of engagement, and whether or not you have a Letter Of Marque. Not all Pirates were Privateers, and not all Privateers were Pirates. Many factors made that determination. For some the lines were clear, others not so much.