I see them at gun shows, but don't know if year of manufacture makes a difference. Often, the ones in like new condition go for around $70.00 at local gun shows. I don't think the older models are made any differently than the newer ones, so I'm guessing your knife would go for $30-70 depending on condition, how many of them are available locally, and buyers "gotta have one" feeling. I checked Camillus' web site, and I don't think they make 'em any more, so that should help keep the value a little stronger. But I think Kabar still makes knifes like the Camillus.
I have been drooling over a newer model Kabar with a D2 blade for some time. But they aren't the classic Kabar/Camillus profile or blade and handle material.