Questions about the source of a dealer's fragments

I am working on the sources of Attic figure-decorated pottery fragments at the moment. I was interested to see that two fragments of a cup attributed to Euphronios by J.R. Guy (Euphronios no. 50) that had been on loan to Princeton University Art Museum (L.1990.134a–b) are now in the Michael C. Carlos Museum (2005.026.004A [and B?]). (I presume that the other fragment was acquired as the kalos inscription naming Lea]gr[os is on the second fragment. (Does the date for Leagros kalos need to be adjusted?)

The history of the fragment is provided as follows:

Ex coll. Peter Sharrer, New Jersey, acquired European art market, 1982-1983. Purchased by MCCM from Sotheby's New York, June 7, 2005, lot 26.

Sotheby's note the following:

acquired together on the European art market in 1982/1983 as part of a group of fragments by various painters

What were the other fragments acquired by Sharrer in 1982/83? Where are they now? Who acquired them?

But the more interesting question relates to the identity of the "European art market". Who was involved?

Why the interest in Sharrer? He supplied a fragmentary Roman relief to Princeton University Art Museum in 1985 that was returned to Italy in 2002 after it was realised that it had been found near Tivoli. Moreover, Sharrer was the source of a fragmentary Attic figure-decorated lekythos attributed to the Pan painter that was donated to Princeton in 1998 and again returned to Italy.

Were any of the pot fragments sold by Sharrer to another major North American university museum also derived from the same "European art market"?