all beers have certain guidelines they must follow in order to be considered as X-type beer. Color, flavor profile, ibu's, et al. All of this begins to put a limit on the ingredients that can be used. I.E. - you can not use Crystal 120 in a pale ale, I mean you CAN but it won't officially be a pale ale. So, in general all beers of a particular style will be in the neighborhood of similar. Obviously the ingredients can still vary a great deal; weight, hops, hop addition times, yeast varieties, ferm temp...etc.
Just because you and the burger joint down the road use similar meat, spices, cooking processes, and bread do you not consider that YOUR hamburger when you cook it?
One more thing to consider...a local brewery made a wort, split it in half and used a different yeast in each and named them different names. I'd say it's what you are comfortable with in calling it your own.