The really rare GNX stuff are things like the fender collars and the stuff to make the vents functional.I had to bother Joe Harrington forever and a day before he'd sell em to me.
I bought 3 GNX dash plates last month on ebay for $125-$175.Real GNX parts= big $$$$$$$.Things like those vents are basically priceless...I know the only way my GNX spare parts are leaving me is if someone wants to trade a complete,running,mint,low mile GN for them.
And if you ebay much.youd know that seller has changed his name many times and has had his GN parts on there for at least 2 years.