Was Kleisthenes or Pleisthenes Archon at Athens in 525 BC?

A fragment of the inscribed archon list now known as 'IG' I³ 1031 was discovered in 1936 and published in 1939. When this fragment ('IG' I³ 1031a) was restored to yield the name Kleisthenes as an archon at Athens in 525/4 BC, scholars were naturally excited, as several things were presented to them at once: a new piece of evidence for this Kleisthenes, immediately identified as the Athenian reformer of 508/7; the chance to correct Herodotos in what could now be claimed to be a piece of Alkmeonid propaganda that the family had been absent from Athens from 546 to 510 BC; and above all, a different conception of the nature of Athenian politics under Peisistratos' successors, his sons Hippias and Hipparchos. But have scholars been too hasty in accepting such a restoration? After all, restorations can be battlegrounds for scholars, and yet this particular one has evoked very little negative response. In fact since Alexander criticised the identification of the fragment 'IG' I³ 1031a as part of an archon list, the verdict about an archonship for Kleisthenes in 525 seems to have been unanimous. Thompson who supported the identification, against Alexander, at least wrote that 'Meritt's reconstruction is 'extremely probable' (my italics) but even this caution concerning the restoration of the name of Kleisthenes is no longer exercised.