Rikki ... in all my years, studying, playing, and teaching accordion, regardless of whether a person was right or left handed, the keys were always on the right hand side ...
Although I did see a fellow busking in Italy with the keys on the left side ... the notes go from low to high from the 'top' of the keyboard, same as if it were horizontal going right to left ... it was strange watching this fellow as he moved down the keyboard and the notes got lower ...