Yes you can but only two of the holes and screw sets match up. It seems quite rigid...I just tried it.
For Vertical Carry: I removed the clip ( as shown in your picture) turned over the plate so the smooth side is out...then re-attached the clip. Attached the plate to the right side of the sheath...and carry it in either my back pocket or front. The clip is exposed on the outside of the pocket and the knife is inside the pocket. A little more secure and rides closer to the body. When needed ...it allow you to easily unclip the sheath from your pocket with your index finger and put the whole unit in your pocket.