I don't have the time to go into the whole hybrid/GMO question, but the short
answer is, you are safe. Bad news, Lon Rombough recently passed away. Go to his website anyway, there is a lot of good info there. Just be aware that you can't order cuttings there, which is a shame. I got cuttings from him last year and was planning to order more. He also wrote a book on grape growing, and it is still available from the website, though you can buy it other places too. His son was going to try to fulfill the book orders, but I don't know about the status of that. Another good source of info is the North American Fruit Explorers. Many states also have fruit and nut growers associations that are wonderful sources of
local info. In Indiana we have a wonderful group of people who are very knowledgeable and generous, and in March we have a scion swap where you can get many varieties that other memebers have donated. Many internet forums such as this are nice as far as they go, but to get the most reliable info, find someone local to you.