Not sure what you mean, but don't you agree that, if we take 0 to come before 1 and not after 9, there's an asymmetry between the left and the right hand?
Both yes and not. There is some asymmetry in wrist's angle but there is kind of a symmetry that you have two keys left from our 7 and two keys right from my 8 (your 6). If I understood your POV correctly then you seems to consider the position of [ and ] symbols in Programmer Dvorak as symmetric for you.
No, on a regular keyboard I regard 4 as corresponding to 7, since they are both pressed by the index finger directly above the home position. I see the numbers as split in odd and even between the left and the right hand.