Hi pena,
Unfortunately I’m not familiar with Green Mattress Company.
There was a Green Mattress Factory but they were in Ohio (and later on in Maine) but if they are related to them or Dremata or any of their other websites that they have had over the years then you will find more information about them in post #5 here and the posts it links to.
If there is still a sticker (or perhaps part of a sticker) on the Talalay layers inside the mattress you would be able to identify whether it was Natural or Blended Talalay and which company made it but if there isn’t then there would really be no way to tell.
If you are looking at a private sale for a used mattress then you would be able to tell the manufacturing date by looking at the law tag and there is some information in post #2 here that should be helpful as well.
If the mattress is being sold by a liquidator then some of the information in post #8 here and post #2 here and post #2 here would also be worth reading.
Phoenix