ADCAEA: Collector of Egyptian Antiquities

I have been reflecting on the Association of Dealers & Collectors of Ancient & Ethnographic Art (ADCAEA). One of the three board members is Joop Bollen. Bollen is a collector of Egyptian antiquities (see "Joop Bollen, directeur South Dakota International Business Institute", volkskrant.nl 2 February 2002 [translation here]).

In 2011 Bollen donated an Egyptian mummy mask to the Michael C. Carlos Museum (inv. 2011.017.001). No further information about the prior collecting history is provided on the museum's website. There is a short piece about the gift on the Emory University website ("Art Collector Donates Rare Works to Carlos Museum", Emory Magazine Winter 2013).

These are not the only gifts to the museum:

Collector and friend Joop Bollen has donated several important Egyptian works of art to the Michael C. Carlos Museum, including a Middle Kingdom wooden sarcophagus and a large Nineteenth Dynasty limestone relief slab called a stela.

What are the full documented and authenticated collecting histories of these three pieces?

There seems to be an association with the Egyptology curator at the Museum:

Bollen, a business leader based in South Dakota, is a longtime collector whose interest in antiquities led him to a close association with Peter Lacovara, senior curator of Egyptian, Nubian, and Near Eastern Art at the Carlos Museum.

If ADCAEA is promoting more transparency ('open communication') in the antiquities market, we would expect to see disclosure when collectors donate to museums.

And whatever happened to Culturegrrl's request to the Museum? (Or, for that matter, mine?)