I'm sure she'd heard about some of their projects, anyway. But that sort of bluster was pretty common in diplomatic greetings back then. Probably still is, really.

Fun fact: the letters that the US President sent with Commodore Perry, to force the opening of Japan, were addressed to his majesty The Shogun, Emperor of Japan. This may reflect the one time that American diplomacy has respected realpolitik more than an ideological delusion that everybody really wants to be American and just sometimes gets misled by evil actors away from that.