according to Tourney Rules
http://new.fantasyflightgames.com/ffg_content/agotlcg/support/AGoTTourneyRules.pdf
A Clash of Arms:
(F13) Pyromancer’s Cache
is legal for Legacy Tournaments
but according to recent GenCon posting
http://new.fantasyflightgames.com/edge_news.asp?eidn=679
A Clash of Arms:
(F13) Pyromancer’s Cache
is NOT legal for Legacy Tournaments at GenCon
Which posting is the Gospel?