Hang on, though, I just realised: the painting is from 1737, which means it can't be Gundling, it's Morgenstern. This said, maybe the painter did something like the painter who did a family portrait of Henry VIII with all his children (Mary, Edward, Elizabeth) and Jane Seymour though she was dead and had been since years when the painting was done? Depends on what FW asked for.
Re: Martin Sabrow's Gundling Biography: I