I collect Auto5 Brownings and have also had a few of these 2k's. I sold my last one to a buddy of mine who still hunts with it every year. My local gunshop usually has all the used Brownings in the same rack so I see the prices every week. One big thing obviously is condition. I've seen these 2k's around the $300-400 range that show honest wear or have scratches, maybe some minor pitting or a modificaton etc. Better ones with only minor blems are in the 450 range. All out new shape 550ish. The other thing I've noticed though is they don't move much. I stop by this shop at least once a week, sometimes more, and many of the old Brownings sit in the racks for a long time with an ocassional sale or new addition. What seems to get them moving is every so often they will have a clearance sale and mark them down or give 10 or 20 percent off etc. FWIW, the one I sold my buddy was like new with original box and papers, he offered me $350 for it so I sold it to him. I was happy and he was happy. I feel it was maybe worth $50 to 100 more than that but then he's one of my best friends and you can't put a price on that. If he had offered me 200 I probably would have said yes.
I collect expensive hobbies.