I once saw a key to adjust the gasvalve on an SVT-40, so i asked the guy how much it was, he said 70 euro, i laughed and walked off, i am not going to haggle over some ridiculous price like that. The next day i bought it on Ebay for 40 with shipping included. Still found it pricy.
About the shell, i will offer 500, i bet it will end up being close to 600 or maybe more. A lot but its a rare shell.