No-Questions about a Statue Offered by Christie's

In the upcoming Christie's sale on Thursday there is a headless Palmyrene seated statue (funerary monument) lot 95 estimate $25,000 – $35,000 with a collecting history which cannot be traced back beyond the Assads or the 1963 Antiquities Law (Legislative Decree N. 222 Oct 26th 1963) with any certainty. It says "Private Collection, Montecito, acquired prior to 1996; thence by descent". Montecito is Santa Barbara, California - how did it get there?  The online catalogue photo is zoomable. Have a look at the surface of the limestone, interesting. Now move down to the base.

Grey gunk, cropped screenshot from the Christie's website

What's that? Grey gunk applied with a spatula, looking for all the world like Portland cement smeared on. What's it hiding? Couldn't be fresh crowbar marks could it? What does the "condition report" say?  When was this fragment removed from what, and how did it get to the USA?  Go on Christie's, do the decent thing.