That was 25,000. You are quite a bit off there. That film had grain about equal to current ISO 400 films and produced a positive image by heat processing.
Yes, they can make that film and they were petitioned to do so, but refused. It will not be produced. The inventor is going to give me the patent # when it issues so that I can try to make it here at home.
If I succeed, I should be able to achieve about ISO 2000 here at home. I have no idea whether I will be able to or not.