I have the HAC in Box leather with the round turn-lock. These were present in the older HAC's....the newer ones have the square lock.
LARALAMB.......don't be sad about buying Courcheval....it's a lovely leather and you have a gorgeous bag! With all Hermes bags (with the possible exception of Togo or Clemence) you just have to be a little careful. Each leather has it's own quirks....Chevre with scuff, Swift will scuff, Box scratches and marks, Barenia actually changes color (darker with a rich patina over time)......this is the beauty of Hermes leathers, IMO.
I brought my Gulliver Kelly to the spa just about a month after getting her because I didn't know about the corners scuffing in this leather....I almost had a heart-attack! But I was assured that my baby would come back good as new so it's all good!
Just enjoy your beautiful bag........Courcheval is a lovely, lovely leather!!!