Collection History of Clunky Escutcheons Questioned

Particularly unlovely and 'clunky' escutcheons with
odd patina and unclear collection history (Sotheby's) 

Sotheby's A Pair of Etruscan Bronze Attachments, circa early 5th Century B.C. Estimate: 50,000 - 70,000 GBP [...] 

Provenance
Mathias Komor, New York, inv. nos. I.514 and I.515
Clarence Day, Memphis, acquired from the above on February 24th, 1978 (Sotheby's, New York, Antiquities from the Collection of the Late Clarence Day, December 7th, 2010, no. 15, illus.)
acquired by the present owner at the above sale

Note that part of this collection history seems to be known only because this item passed through the same auction house two times. The all-important question is where was it before Mr Komor got it, reportedly by 1978? How did it leave the soil and territory of the source country? Without the answers to those questions, this is only a "they can't touch you for it" provenance. It in no way establishes licit excavation and export before it "surfaces" in these records. Prof Christos Tsirogannis suggests there is part of the collection history missing precisely here ( Dalya Alberge, 'Antiquities for auction could be illicitly sourced, archaeologist claims' Guardian 7 Dec 2021). It seems not enough questions were asked by the auction house when they agreed to host this sale. You'd think Sotheby's of all people, with their reputation, would be being a bit more careful over things like this by now.