SJGames uses the Yen sign for foot noting, but a quick look in my copy shows no foot notes, however my 1999 edition has had white out applied and corrections applied so that you have X's, like so;
4 cy: A grave. 6’× 3’× 6’ deep. 5 hours,
20 minutes.
My assumption would be typos, but the 1999 edition is not listed on the errata page, here;
http://www.sjgames.com/errata/gurps/