How tough are the original Tridents ?

[Knivesaretools]

Also there seems to be a slight difference, I know there were likely several 'variations' but the one with what appear to be yellow washers in the handle also seems to have a 'straight' first spine grind, whereas the white washered ones go across at an angle ?
The spine towards the tip also seems a little thicker on yellow washer hilt knife, actually thickening towards the tip.

Were all these early models made by Hattori ?

Any thoughts, info on steel differences on these earlier models appreciated