Yes. I think a team should at least consider having at least one left handed player. This allows more "looks" at potential lines of sight. Sometimes there is a line that is more advantageous to a left than a righty. I would suggest the lefty throw first at the beginning at the game at the left kubb on the baseline, assuming your inkastare is a righty.
Secondly, if your lefty is a good inkastare (or kubb tosser), they can provide an advantage depending on which centerpin you are throwing to, if you use the corner strategy.
Perhaps you have two good inkastares on your team, one is a lefty and one a righty. You may find situations where you split kubb tossing based on the situation. It provides a lot more situational kubb having both lefties and rightyies on your team, in my experience.
Our team recently picked up a lefty, and we are looking forward to the advantage!