TTTT - the dynamics of fastening the clip are different. The Endura uses a left/right clip that attatches with a barrel style bolt through a hole in the handle. Tip down has to be screwed to something.
There is always the possiblility of fastening the clip to the pivot, but this magnifies the dynamics and the manufacturing costs (ergo; retail price) considerably.
We''ve made knives with holes top and bottom, left and right for screwing clips to. Complaints were then too many holes, how to fill the holes, dirt in the holes, etc. Not a simple problem. As new models come out, we're again paying more attention to left, but they will be tip up or down (at our currently technology level).
sal