If I remember it correctly, once an answer has been selected as best, then others can no longer provide their answers but are only allowed to make a "reply" or "comment" on other people's answers. Now that you've asked for this, I see that they still allow us to answer questions that have already been settled.
To answer your question, yes. I do read answers to questions even if it has already been awarded and I no longer have the chance of being selected. I read them for the purpose of knowing other people's thoughts on the matter and learn something new. If I have something interesting to add that hasn't been mentioned previously then I will write an answer as well