You translated correctly. Re: English wiki entry - that hadn't been there yet the last time I checked! So clearly someone else noticed. :)

BTW, while Voltaire writing to Madame Denis he's got a soft spot for Fritz' badmouthed Granddad while proofreading the Histoire de la Maison de Brandenburg is inevitably one of the doctored 1750 - 1753 letters, I can't see any advantage in him inventing that observation post facto, so I'm guessing that observation was one he actually made back in the day. And I do wonder how Fritz reacted...