JLW's "Something Else" just says Jerry Garcia; I assume JGMS. It is possible that this is the "sometime before Christmas" gig mentioned in Night Times , though that had a 12/23/71 listed publication date. If it's not this 12/22 gig, then there could have been one on 12/24.
listing: San Francisco Chronicle, December 22, 1971, p. 42;
mention: [possible] Night Times, December 23, 1971 - January 3, 1972, p. 5;