At least in the catalog it is offered in addition to the 700x40. It could be that they are actually the same tire from the same mold and they will be labeled 700x43 going forward, but given that they make a few other sizes that close in size it's highly plausible it is a new size. That's 26, 32, 35, 38, 40 and 43 in the 700c SK.
I forgot to mention that the 650bx48 slick version shows the same expected arrival date at the end of July just as you were told in April.