I was able to change the font of a UI Text element, by importing a .ttf (TrueTypeFont) file into the asset section of the UI editor. It also worked to change the font, by selecting the text Element and under asset selecting the imported font file.
var canvas = new CanvasScript("NameOfCanvas", "font.ttf");
//Canvas will default to default font if font parameter is not specified.
//Note: font file need to be in `Bundled` folder in order to get detected.