There used to be 3 differing versions of Tri-X (same generation) when I began photography in the 1960's and the Kodak film developer datasheets listed different times for each.
Originally Posted by StoneNYC
Tri-X was made in at least 3 factories in the 1960's, Eastman Kodak (Rochester), Kodak Canada, and Kodak Ltd (Harrow, UK), just before WWII it was also made in Hungary. The differences in speed/dev times depended on which country the Tri-X was made which was printed on the boxes. Each company supplied specific markets so in most cases you wouldn't come accross the other two versions, but of course this was critical to photo journalists travelling around the world.