I am not familiar with that manufacturer. Regardless, I would guess that the table is not intended to use k66 cushions. You can check the nose height (distance from the slate to the nose of the cushion). That dimension should be somewhere in the proximity of 1 7/16".
Aside from that, you can feel the bottom side of the cushion. Check to see if there is a defined ridge where the rubber meets the wood. A very pronounced ridge would suggest that the rail is intended to have a K55 cushion or a Monarch Superspeed. Of course, making this determination may be somewhat difficult, not knowing exactly what you are trying to feel.
