I have looked in the Procedures Manual, and I find no mention of it.
I would say that it is not necessary, as that info is on the Cert, which is now posted with every course map.
Just looking for consistency. I have no problem putting the info on my maps, as I want more work. But, if someone doesn't want to be called to measure another course, or the course was "found to be short by my GPS", maybe having the info on the map, where it is easy to see, is not such a good idea. If someone looks at the cert, they have put more effort into finding the measurer than most will, and I think that is okay.