There's a general rule in antiques and collectibles, and it applies to our area, too. For any item being sold in a secondary market, its value is whatever the seller and buyer agree to at the time. Another rule which applies is that for the first 30 years of an object's life, its value is purely speculative. That rule comes from Harry Rinker, who is an expert on collectibles, and has written price guides and books on the subject, a regular column, and was the host of "The Collector Inspector" on HGTV. (He's a local boy)
Those are generalizations, to be sure, and as such, there will be exceptions. But in my experience, I've found both rules to be valid. So when I see an item that I think is overpriced, based on what I have seen elsewhere, I have to ask myself whether it's worth it, to me, or if the buyer is not as well-educated about the item. Of course, there's a psychological element, too, and some guys just have to have the item, not matter what.
Just my own observations.
Prosit!
Brad