This is really an interesting area that doesn't get too much light. I've sat in one of the mentioned living rooms in the Upper East Side that housed these types of antiquities. I won't name them, but they were raided and had over 70 items removed because they were stolen from their original location.

It was quite odd to see; they had a massive database containing pictures, values and auction histories of all their items in FileMaker Pro. You walked in their apartment and you were greeted with a table (itself an antiquity) containing statues of African origin as well as some of marble from Europe. Large format paintings from the 1500s-1600s lined the walls of the living room I was allowed to walk through - they were very protective of where I was able to walk in my capacity of "IT guy".