When I first arrived in China one of the things that I was most interested in concerning food was being able to try truly authentic Chinese dishes. After a few months here I became aware of the fact that many dishes change depending on which restaurant you go to. This led to my asking an important question.
What I've found is that often recipes change from one restaurant to another. There are many reasons for this. One is that often the cooks in each restaurant use family recipes that they were taught at home by their parents. Many restaurants are family owned. Sometimes they use recipes that were taught to them by other cooks. Also, it is common for restaurants to want to create special dishes and to make things their own. A restaurant may change a recipe slightly in order to differentiate themselves from others. Variations of a dish are also created due to regional differences.
This last reason means that if you order Gongbao Ji Ding in Sichuan province you will be served a dish that has chicken, peanuts, carrots and red peppers. If you order this same dish in Guangdong province the dish will likely be served with cucumber instead of carrots.
Knowing these factors makes the question of authenticity somewhat less relevant because on the one hand none of it is truly authentic and on the other all of it is authentic. If you think about it this means that the Americanized version of Kung Pao Chicken is just as authentic as the original Sichuan variation of the dish or the even more original Shandong version.
With these thoughts in mind I have gradually become less concerned with authenticity and more concerned with what I enjoy.