In that case, no, no one is, no one had heard of him in the time of 1930, thus he was not great for all time...
If you want a literal answer, then I gave it to you. As for the abstract, it really does depend what your evaluation of great is. I would suspect if you really thought about it, you could name a thousand fighters who were better, but that does not mean you do not think he is 'great'.
It would be a tough fight, Zale would win, but he wouldn't think about going out dancing later that night. Or that week .
Hamsho simply wasn’t a great fighter. He was a good contender despite his limited skills and with his toughness,but I don’t think there’s anyway you can describe him as an ATG.