... it is very interesting to see the very rare elder brother of my watch!
the caseback with PROTOTYPE adds great value to the watch and opens with another answer of this watch, the interesting thing is that it seems JLC started to design C-shaped case for this watch, then they finally chose and settled to use rectangular shape.
with this C-shaped case, it looks so closer to Omega C-shaped Constellation, as Arthur asked, does it means the design of this watch was also somehow originally come/inspired by GG???
hope someone out there can help provide answer/hints for us!
stefan