That's the normal type and heat range for that vehicle....the insulator is cracked, which could be why the threaded section separated. The nose doesn't look like it was too hot...strange. May have been a faulty plug, or it was dropped before installing....or was hit hard with something when in the head. Another possibility is cross-threading....the threads do look a bit galled, but it's hard to tell from the pic....did he install a new plug, and if so did it go in easily?
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2004 GS GTP/WS6
3.4" puley, BIG conical K&N filter
14.22@96.5 mph