At least this one is not. I've broken my dominant hand before and then separated the same shoulder, both in the same year, and was surprised to find using sciss

At least this one is not. I've broken my dominant hand before and then separated the same shoulder, both in the same year, and was surprised to find using scissors to be the single most difficult thing to do with my non-dominant hand, other than writing. It took a few months to get it right, but that's it. Not like it's a lifelong deficiency. You just learn later. Presumably, kids with their inherently more plastic neuromuscular systems learn faster than a 44 year-old, too.