Scientific way to prove you are ambidextrous, right handed or left handed? I grew up in a country where my grandmother's generation used to believe that left handed were related with the Devil, so I know many friends that have been "corrected" when kids and now they are right handed.

Is there a scientific way to find out if you are in truth right handed or if you were corrected? 

Assuming you were originally left handed but you were grown as right handed, does that makes you a non-natural ambidextrous?
I don't know whether the following has been used to distinguish natural from "corrected" right handers, but following up on the suggestion from @user3169, the Edinburgh Handedness Inventory contains a range of handedness tasks, many of which would probably not be as explicitly trained as writing or eating, and which thus potentially could be used in distinguishing natural from corrected right handers. 

There is an online version of the inventory here.