There are a few issues with your plan. Shimano Ultegra chainrings are profiled to match Ultegra cranks (which is why you can't see the bolt, it's underneath), and will look off if used with another brand / model of crankarm, if it even fits. The link you have provided is for 50 & 34t chainrings, 36t chainrings are standard for 6800 cranks (52/36), not 67** series cranks.
The days of using anyones chainrings with an crank are on the way out, the latest Shimano and FSA use proprietary designs (off set 4 bolt), and would expect all other manufactures to have their own designs in future.