Macybaby, thank you for posting pictures of your cabinet. I also have a cabinet and I had to go see if somehow the lid opened up. But no, I just have a sewing cabinet.
BlackBerry, I have a White Rotary machine and the knee pedal is mounted on the right side of the cabinet. It is not a Martha Washington cabinet though. When we refinished the cabinet and put it all back together again, we could have mounted it on the left. I am left handed but not sure about being left-kneed. Lol

Or maybe it was modified because the sewer had a non working right leg - or no right leg at all?