Bronze 'Erotic' group from 'South Arabia' in Bonhams

Spotted at Bonhams:

A South Arabian bronze erotic group Circa 2nd-1st century B.C. Depicting a man and woman lovemaking, the man standing, his left hand holding the woman's buttock, his right wrapped around her back, the woman with her legs wrapped around her lover's hips, her right hand at his waist, her left at his right shoulder, the man's genitals and woman's breasts naturalistically modelled, 8cm high

Footnotes (sic)
Provenance:

Anonymous sale; Christie's, New York, 9 December 1999, lot 393. 
Property from the Collection of Alan Dershowitz and Carolyn Cohen; Christie's, New York, 8 June 2012, lot 49.
Private collection, London, acquired at the above auction.

Collecting history is more than a 'footnote'. South Arabia is an art-trade euphemism for Yemen, in which case 'Anonymous sale; Christie's, New York, 9 December 1999, lot 393' is no way to assert an easily smuggled object like this came on the market licitly.Was this object, for example, looted during the civil war of 1994? What documentation did Dershowitz and Cohen demand and keep?

Hat tip, Dorothy King