Leica serial numbers are only strictly sequental on rare occasions, so the batch numbers referred to in lists have a lot of leeway at each end. And it was still possible for a customer to order a black camera and this would have taken the next available serial number from whatever batch was in main production at the time. That your camera is brass underneath the paint also suggests that there is nothing wrong with it. As for the lens, some 50mm 3.5 Elmars didn't have serial numbers, but when they did it could be a faint number stamped on the inner lens ring.