As of this afternoon (8 November 2012), the price of gold on the New York Stock Exchange for precious metals was $1728.00 per US ounce (28.35 grams to the rest of the world). I would be very interested to see how much that long P5 barrel weighs because I highly suspect we're approaching it's value in solid gold at that price. If the long P5 barrel weighs any less than approximately 3.47 US ounces (98.37 grams), it really is worth it's weight in gold.
Damn. It would probably cost less to have one custom ground and CNC machined. Of course, King Tanfoglio probably has crates of them in some forgotten room in his magical Walther Palace and a corner on the world market!
Mein König, could you perhaps weigh the long P5 barrel for your humble servant? I am very curious to see how much a difference between the standard model and the treasure you've somehow come to acquire. Plus, I am secretly curious to see if it really is worth its weight in gold!