After pondering this for several years I've come to a conclusion: I don't know. Some things in the N.T. seem to lean toward simply a description while others point more toward how we should live now as well. It's difficult to come to over-arching conclusions to this question.
I do, however, know one thing. As readers of the bible, we let what we like/enjoy/prefer today influence how we interpret scripture. When we find a passage in the N.T. that describes what we like today, we say that what we are reading is prescriptive. However, when we come across a passage that shows something we do not like and/or do, we say that that passage is only descriptive.
A short reading about the early church in the first few pages of Acts shows this. We tend to like the togetherness they had. We enjoy reading about their getting together for the apostles' teaching, fellowship, the breaking of bread, and prayers. Those things we say are prescriptive. However, we don't like so much how the early church got together every day and how they shared all they had. Those must just be descriptions (so we say).
We must be both careful and consistent in how we read the bible. Honesty is also critical. We all take many preferences and opinions to scripture. This does not mean that we are unable to understand what God is teaching us through the bible. However, it does mean that we face challenges.
When it comes to the description/prescription issue, let's be careful. An awareness of our own preferences is important. Let's not allow what we want the text to say determine what it actually says. Too often this is what determines our answer to description vs. prescription.