EDISON SMITH'S Green/Yellow-Gold King's Manassa Ring Grading and Appaisal Help!

Have just received this gorgeous forest green with yellowish-gold-brown and white inclusions King’s Manassa Ring. It has a slightly deeper green than the pics and looks so much nicer in hand. It sets on a thin layer of medium brown host rock. I read Jason’s 2014 interview with Edison Smith and found it quite informative and remarkable. I have a question about Edison’s hallmarks. All lead back to ESS whereas my ring is marked ES. Was wondering if Edison ever used the ES stamp between '68 -'77? This ring looks like an older piece (of course his works are old school looking), weighs 9.8 grams and hopefully of high quality and maybe a rare mark?. All pics I have seen of this ring say it is an Edison Smith including the owner from AZ. Is this truly an Edison ring with maybe AAA grade King’s Manassa (1" long x 3/4" wide x 1/4" high, 17.5 carats?). Thank you in advance for any help.