Carrying a leg could mean lung or brisket or neither. But I think you're right. And even an unproven dog would find a dead deer. May not be trained to track interdigital gland but would still probably go straight towards a dead deer, depending on how long dead.
The one and only time I needed a dog, I was surprised at how effective it was. He didn't even track. He went direct to the buck. Frustrated the handler because he wanted the dog to track, but the dog knew right where the deer was without tracking. It was only an overnight wait and meat was good, nothing stinky, but the dog's nose could detect what we couldn't.