Roskilde history indicates Faith No More played on Thursday 25th June 1992. However it warns "The band schedule is a representation of this year’s printed programme. Changes in the final programme may have occurred."
http://www.roskilde-festival.dk/object.php?obj=474c0029

CD Database indicates this gig as Copenhagen, Denmark but quotes nothing else. This date and venue may be wrong.

Definitely not supporting Guns'n'Roses on this date.
http://www.heretodaygonetohell.com/history/history92.php