Your right $600 was ridiculous but rarely did a Select card hit that mark (aside from the early years and Immortal sigs)...........
Changing topic a bit.............I would say that the majority of Selects big hits signatures got that price and even more, there was certainly some duds along side the gems but every year had a whale of a hit IMO.
I'm bored so lets go through a few:
2000 Gasnier Legend Sig = $600+
2001 Langlands legends Sig = $600+
2002 Raper Legend Sig = $600+
2003 Lockyer Jersey Sig = $600+
2004 Capt Sigs = $600+
2005 Tradition Poore / Stewart / Tupou = $600+
2005 Power Beetson Legend Sig = $600ish
2006 Tye Williams......
2006 Invincibe Johns Record Breaker = $600ish also JT Medallist
2007 Invincible C Smith probably unders...just?
2008 Centenary Immortals x 7 = $600+
2009 Classic Lockyer Capt = $600+
2010 Dudded with no SeriesII
2011 Strike Slater / Hayne Medallists = $600ish
2012 Dynasty LLBs big $$$'s and Lockyer Signature card $600ish
Looks pretty good and I've left off stacks.
Cheers
Ross