The later AGS models had a parallelogram mechanism (including a piece pivoting about the arbor axis) that made the riving knife rise and fall with the blade (as well as tilt with it. On the earlier ones, it tilted with the blade but was fixed in height. The later one is much preferable, the older one is just a splitter really. I can't be sure from your pics but this may be what you have in your later model. Worth using if you have enough of the bits.