The Montesouri school in Detroit never heard of lefty scissors... I asked them how you can teach pre school without knowing about left handed scissors.
Luckily another one opened up a little later and we transferred our son to that one...
We had them for my brother when we were kids, as he couldn't use right handed scissors. I knew that I couldn't use the green handled ones that said "Lefty" as they wouldn't work for me...
We also learned that we could only sit on one side of each other at dinner in booths as if we didn't we kept bumping arms while eating. Our favored arm has to be on the outside, not inside...