i don't know but i think it's natural to want something for each hand at that age. some toddlers, when learning to walk, want to hold something in one or both hands.

when my nephew was about 2 he wanted to carry around some little toys, people or rectangular blocks or something like that. they were different colors and he 'had to' have the same ones in a particular color order in his hand before toddling off. if they got out of order he started over. Today he is a teen with no OCD symptoms at all.

I think there are times in development when independence is being learned and practiced that can seem like OCD symptoms but is really a normal way of doing things routinely (a way of learning) and stubbornly (independence) and is completely appropriate for that age.