I'm not so sure about paper valuation but I believe valuation, be it in watches or other forms of investment, is subjective based on demand and supply. You can only possibly get a rough estimate of the watch price through online research of preowned prices through forums/shops etc. This is also an estimate cause prices posted may not be prices sold. Similarly, different countries have different demand as well. And prices in 2011 would highly likely be different today.
So to get it on paper, I'm not to sure about that.