I think people who do sports with their dogs are likely to be able to see these preferences easier. I do agility with mine and there’s a lot of time spent watching their feet and seeing where and how they start and land jumps and such. He tends to favor his left and will typically lead with it. When we’re doing scentwork he also raises his left paw to signal as well. He uses both paws for all sorts of things, but I believe he does favor his left!