Getty returns terracotta head to Sicily

Head of Hades, about 400 - 300 B.C.
Source: J. Paul Getty Museum inv. 85.AD.105

The J. Paul Getty Museum has announced that it will be returning a fourth century BC terracotta head to Italy [press release]. The press release makes it clear that comparative material was found at Morgantina and that fragments from the hair were found in a sanctuary confirming its original location.

The press release tells us that the head was acquired in 1985. Daniel Ng and Jason Felch ("Getty Museum to return Hades terracotta head to Sicily", LA Times January 10, 2013) inform us that it was acquired from Maurice Tempelsman. The original source was Robin Symes. Why did the Getty omit this part of the collecting history?

This raises the question about other material in the Getty that was sourced from Robin Symes.