Yes. If you split the map in two from 00 to :30 you see on the bottom side the same distance between the key stones. The distance between :30 and the marked drops is the same. The key stones are exactly mirrored compared to each other. Not the mirror over the entire clock (well, that does work like I explained in the beginning of this post, but that's not what I mean. The keystone on the 20 - 24 part is exactly mirrored on 35-39.