Open research question
Establish whether the heads were discovered in 1971 or 1972 and, if 1971, determine the earliest surviving contemporary record that confirms the year and, if possible, the month.
A source, research note, or further-reading link closes this question when staff accept it. Evidence and corrections stay attached for staff and do not close it by themselves.
Staff review every contribution before it is added to the file. A correction is a proposal: accepting it does not replace the official record. Rejected items are handled like rejected case submissions.