I could find nothing in Parts 61, 67, or 91 regarding such a reporting requirement. 61.53 would have been the most logical place for such a reporting requirement.
There was a change in 2004 to 61.53 but I believe it involved the addition of light sport material.
The only 60 day reporting requirement that I'm aware of is related to motor vehicle actions per 61.15 (involving drugs.) There is also the 30 day change of address reporting requirement.
If you still have the letter and can see what regulation it cites that would be helpful.
