Machine made? - Not necessarily - it's a natural material and the end product, or even the original cleft - and handle - would be weighed as a whole and maybe not checked to see where most of the weight is concentrated. Just as you can get bats with identical dimensions that will have different weights, you could get a cleft that has more 'weight' in one area than another. However, in respect of the handle material - cane - when using it for other purposes I've checked density via flotation. Some cane sinks, some floats, and weirdly - some sinks at one end and floats at the other, which suggests there is more weight concentrated at one end, even though the dimensions were the same along the piece. So maybe if the handle, by fluke, had cane that was slightly heavier at the top, you might get a very subtle counterbalance enhanced pick up?