That sawed off shotgun still looks suspiciously of legal barrel length and I think woth OAL its right on the mark for being over 26"
Figure that AR has a 16" barrel plus a 2" muzzle and roughly a 6.75" stripped lower, should make about 26".
Edit:
So I did some digging and some napkin math. That AR looks like a M+P ii, which means its overall Length is 35" and it has a 16.1" barrel.
AR lower measures 7.5" from the rear to the center of the front pin, Measurement should be about 4.5 inches from the rear of the receiver to the mag well.
Center of the front pin to center of the mag release is 3.08"
Soo. If you take the 16/.1" barrel, add the 7.5" receiver you have 23.6", that's 3" short of shotgun legality.
But, if you take that same length (take a piece of paper, line up with the rear receiver, draw a line on the end of the AR barrel) and compare it to the sawed off shottie you'll see that only takes you to the left most portion of the magazine plug ring. Take the remaining from there, compare it against the magazine from front pin to ejector, and you'll come up with your other 3 inches.
It aint perfect science, but I think it meets the rules, except for maybe the pistol gripish thing going on.