911s 911r 911st exhaust mount value

[opposed forces]

I posted earlier today to try to identify an exhaust mount i have. i figured it out and now i need to know the value of it. see this link, it is the same mounting bracket
http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/303354-rare-nos-911r-911st-straight-pipes-end-pipes-trumpet-style-bracket.html

part # 901-111-153-00 i will attach better pictures tomorrow but it is nos with shelf wear and scratches. i have a standing offer but i need to know the ball park value. after i know i MIGHT put it up for sale but this isn't an auction or a classified ad just a post trying to determine value. Thanks, Andrew