Its not so much the value Patrick, but I come up with the theory that many get destroyed due to folk trying to remove the axis pins without removing the very small hardly visable reataining pins, the big mistake is that the axis pins have a slot for a screwdriver that indicates to most it screws out, its not the case this just enabales it to turn so the retaining pin hole lines up with the sight ladder........
I do have a slider( but but no ladder) the retaining spring is missing or need replacing, PM me if interested.