Salaams Harrywagner, My first point is to advise a quick look at
http://khanjar.om/Types.html which is the new government site on Omani Khanjars. It is far more detailed than any other publication and stitches together a number of different Royal types. This is really the only Khanjar that comes with a discernible date ...the others all seem to float in from about as far back as the 16th C in styles of regions...also on the same site ...which have morphed and mingled into what we have today. The Royal form has, in particular, followed a difficult path still being unpicked as elements appear in some Yemeni, Saudia, Bahraini, East African and Zanzibari weapons probably through trade by camel train and ship.. Place
The Omani Khanjar into search for more information.
Regards,
Ibrahiim al Balooshi.