All of my Brooks saddles are uniquely and slightly imperfect because, as you correctly point out, leather is leather. It's the nature of the beast. Plus the assembly process is all done by eyeballing and feel. Lot's of room for inconsistency.

That said, I believe the OP's saddle was assembled poorly. Poorly enough that I would not accept it. It's flat out crooked. Look at the top photo. Look at where the leather was riveted to the cantle plate. Compare the gaps between the leather and the cantle plate at the furthest right and left, they are not uniform. The leather was riveted to the cantle plate significantly off center to the right.