Hi reminQo! Welcome to SWLS. I think it's a good topic, one I'm curious about, at any rate, but hope you don't mind, I changed the title to "4 toes" so people don't get confused.
Check the Investigations section, also, because sledge and I found a good reference to an old Peacock novel about a statue with 4 toes. I don't know if its an allusion to that.
I agree that it makes you think the Colossus of Rhodes. Other random imagery it brings up, include Atlantis and even Planet of the Apes. I personally think they are trying to suggest an ancient civilization which had evolved to be a little different from modern humans. But you could go a million different ways on it. I think it was one of the most striking scenes in the finale, now that we're introduced to another island mystery.