Paperwork and documenting collecting histories

One of the issues that I keep mentioning is the need to authenticate documentation. Paul Barford has provided an excellent example in his discussion of material from Palmyra surfacing on eBay. He mentions an "Unconditionally guaranteed authentic" Palmyrene funerary portrait that is being offered on eBay for $13,500 (and on offer today). Its collecting history ("provenance") is provided: "Ex: European art market; Early American private collection, 1960's".

However the invoice indicates that the stela was flown from Beirut to JFK (arriving on 10 April 2006; customs entry 10 November 2006) by Malev.

So are we supposed to believe that this portrait surfaced on the European art market (no evidence posted) and then passed into an "Early American private collection" in the 1960s (no evidence posted)? And then shipped from USA to Lebanon (no evidence provided) so that it could be returned to the USA in 2006 (invoice provided).

This raises all sorts of issues not least the paperwork seen by US Customs in November 2006.