chasil is talking about a star that was able to form an iron core naturally through fusion, not a thought experiment of a ball of iron with the same mass as the current Sun.
This hypothetical is getting into "if my granny had wheels she'd be a wagon" territory.
I interpreted the original comment as if the Sun, with its current mass, had an iron core. A star with the mass of the Sun cannot have produced iron, so it would have had to have formed with an iron core. This is certainly ruled out by other data, of course.
