The FAA will not/ does not stamp logbook......I had it notarized and that kept them happy. On the other hand if you have any supporting documents, tax records , any flight time records from ECREW/ Aims it can help add some legitimacy to logbook.
Also I can't remember if for interview or start date but needed to request records from FAA...again the FAA will not give you your PRIA records....the request has to come directly from the CAA in Qatar and will be sent to them only, and they know this so don't sweat it and kill yourself trying to get this done