Yeah, in some countries it is pretty common to find people named after a surname. This happens in the U.S. but also in some other areas of the American continent: for example, I noticed that a lot of Brazilians are named after some English surnames, even though I can't really figure out why (I mean, Brazilians named after English surnames, not Portuguese ones).. Anyway, this is a trend that has been going for centuries by now, back in the day it was even more common than it is nowadays in some countries (like in Europe, where it is not such a common trend today but it was in the past). In a way, this due to the fact that centuries ago there was not such a neat distinction between first names, last names and even nicknames, the onomastic system has been strongly and continously "under construction"..! A good example is the "trinomina" system that was used in the Roman anthroponymy, where the original distinction among praenomen (first name), nomen (surname) and cognomen (nickname) slowly disappeared and what was at first a nomen, for example, would later be used as a first name and so on. In short, onomastics is rich of such incoherences and I guess that this is what makes it interesting and fascinating, just the fact that it keeps developing through popular tradition over the centuries, in a way that is often as nebulous just as popular heritage can be.