It's not "required" but highly recommended if you want it done right. By that I mean removal of the existing paint and primer, fixing and imperfections then repainting the piece correctly which I believe includes baking it. I paid a little under $500 for the complete R&R and painting by a top notch shop. You could save a few bucks and just have it re-sprayed but as is often said....You get what you pay for.
Besides, it's an NSX, not some mass produced piece of junk like a Porsche or Vette. Treat her like the hand built automotive masterpiece that she is!