I honestly don't know if you base it off of the front or back of the clamp.  Never fletched with feathers before only vanes so left wing right wing didn't apply.

With feathers don't I have to match the left feathers with the left clamp and same with right?

 

That looks to be just the opposite of my left wing clamp when I eyeball it as you be holding yours. So I believe it be right wing clamp. And yes, you do need left wing feathers for left wing clamp and right for right.

Yep, that's a right wing clamp.

The back end of the feather will go to the left making the arrow spin clockwise as you see it go away from you. Righty tighty, lefty loosey.