It sure looks like the same one.
I suppose you could mount it on top of the flip up armrest, but it sure would be an odd place to mount it. You'd also lose the regular function of the armrest. Where would you rest your arm?
It may fit inside the arm rest, but you'd have to measure. I know the $40.00 armrest available at the dealer will fit inside the armrest, but it's too expensive and not as good as this $15.00 model.
The second one I ordered didn't arrive today, but when It comes tomorrow, I'll have a look see.
Btw, I had one mounted on the floor between the seats in my Nissan Quest minivan and it worked like a charm. I held it in place with velcro on the side of the seat, and folded it up when I wasn't using it.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".