With the decline in shotshell handloading (due to cheap promo loads and the cost of components), the market is smaller and the values less.
They may be $525 new, but most on the EE that I have seen were listed in the $150 ballpark, and didn't seem to sell quickly.
If you are considering parting any of it out, I might be interested in the bushings, as I had a 12/20 PW375 given to me by a coworker and am still getting it set up as it only came with 2 shot and 2 powder bushings.