There is a nice selection of generic travel trailer furniture out there with which to modernize your vintage Airstream.
The front, jack-knife sofa in my 2007 Classic Limited is widely available. It is not a uniquely Airstream product, though the arm cushions and trim are custom made.
It is a beautiful sofa, but no fun to sleep on. So, try before you buy.
The original gaucho that came with your Airstream remains unsurpassed for sleeping comfort as far as I know. Others will confirm or contest this opinion.