OK, now I'm confused. The font family usually works to supply proper bold and italic type when the entire font family -- all four fonts -- is present on a computer. In this case, only one font would be present. Do the bold and italicized versions somehow get encoded in that one font? Or does the reader merely guess?
If the latter, that would explain why the italic type for the default font looks exactly like the normal type, only pushed a bit to the right. But if it's the former, it might be worthwhile to change the default font after all.