This is common on all the lens reviews I have seen in these older magazines. The first one I posted was from the January 1979 Popular Photography magazine as part of the Minolta XD-11 review. This one is from a newer December 1982 Popular Photography as part of the FM2 which shows a Nikkor zoom. As you can see, the actual T numbers are very close to f numbers marked. I can only imagine that the superb Canon 70-200 f2.8 L lens is as good or better in this regard. Unfortunately, the review of it doesn't show this info nor in Canon's specs. Since the older lenses are for all practical purposes close enough, they probably are no longer concerned about this bit of data anymore.