I been using NK4 or K4v2 The K5 is the the Kindle Touch. The KPW is a given. We wont know the firmware number till it ships. Then we will know what number to give it. The Kindle Fire is a K6.
If you say you have a K5 people are going to think it's the KT. It's getting confusing as the name game has changed but we will get it figured out.