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The map shows only those seats that have been pre-assigned (Golds, Silvers, ticketed in J et al). So, your chances aren't that great (note that 64A also becomes free at T-24 if not needed for a child). However seat availability can and does fluctuate and you might find seats become free before then as people cancel bookings, change flights etc.

If it is a 70J plane (Club in rows 12-14) there are some choice seats there too - 12J, 14AK.