The story of the Browning High Power pistols with Omani national crests is and interesting one. It begins with a man named Paul Van Hee brokering a contract for Cadillac-Gage “Commando” armored cars for the Omani government in the late 1960s. These were to be equipped with FN MAG machine guns, and it came to Van Hee’s attention that Oman might also be interested in High Power pistols. He wasn’t an FN agent, but figured he could make that deal happen (and presumably make a nice profit on it).
Van Hee imported 36 new High Powers into the US, and then had them engraved with Omani crests (although the first 9 were accidentally engraved backwards). Around the time he was showing the guns to the Omani delegation, though, the deal fell apart. FN got wind of it and arranged the sale themselves, eventually shipping one 5,000 pistols to Oman (without any special markings).
The demonstration guns remained in the US, and were sold off onto the collector market having never actually seen Oman. Interestingly, they are exempted from the NFA when fitted with original Belgian shoulder stocks, like this one is.