Do you know how fast your Barnevelder hen feathered in as a chick? I'm inclined to think they're a slow feathering breed because of the intricacy of their pattern, but not sure if that's actually the case.
If she was slow to feather in, then you would have created sexlinks with the cross. Legbars are fast featherers generally speaking, feathering in more at the rate of the chick on the left in your picture, and crossing a fast feathering male to a slow feathering female produces feather speed sexlinks where the male offspring are slow to feather and the female offspring are fast to feather.
However, if you don't know how fast the mother feathered in, then I would definitely wait to be sure on their sexes. Sometimes chicks feather at different rates for a variety of reasons, even within the same breed or cross, so it could just be one of those things. I'd just keep an eye out on the slow to feather one to make sure that he's keeping up otherwise.