WHOOPS! I stand corrected - at least as to which side it folds. All the pictures I see of the "brace" version (these Rifle Stock version pictures don't show it folded) of this item shows it folding to the RIGHT, ejection port side.
AND yet, looking as closely as possible to the pictures (zoom), I still think it MIGHT be possible to unscrew the "arm" from the attachment device, flip that over, and then reattach the arm and be able to fold it to the other side. I'm going to send Strike an email with this question.
cservice@strikeindustries.com
Looks like left side only (opposite side from ejection port). HOWEVER, it might be possible to flip the attachment piece (that goes to the picatinny spot) so it would go to the right side (ejection port). AND, it is advertised as a "single side" device. I'm looking at the Strike Industries site, and it doesn't specify which side, nor does it say anything about possibly being able to switch the side.