I just unboxed a Doppler knife and someone offered me a huge overpay because they called it a "Phase 4." I thought all Dopplers were worth roughly the same amount depending on the wear. Why does the specific phase change the price so drastically on the market? The person offering the trade seemed very insistent that the amount of blue on the blade makes it a collector's item. Is there a specific chart that shows which colors are the most desirable for this type of finish? I want to make sure I'm not being tricked into a bad deal.