Thanks everyone. The conclusion I reached from talking to an EE friend of mine was that it wasn't necessary to find out which was hot and which was neutral for a simple lamp fixture. So, I hooked it up and it is working.
As far as updating to code goes, that is good to know. Since I am renting, I'll make sure not to get to that number.
I just have two identical fixtures I want to update. My girlfriend owns a house though and also has K&T and is considering similar work so I'll make sure she knows.