marantzman1
Do an eBay search on Heil ESS AMT, especially in the "closed" auctions section, and see if anything pops up. The "closed" auctions used to be a real treasure-trove of auction-based market-value information. Before they adopted the policy of deleting closed auctions older than a month or two you could see what price items sold for, or just as importantly what price they did NOT sell for... selling prices were remarkably consistent from one auction to another.

One dealer was selling a sizeable quantity of Chase-Durer UDT1000 watches on eBay, one watch at a time, and even though I bought one $1 above the extreme lower price limit, the prices for this entire group of Chase-Durer UDT1000 watches varied LESS THAN +/- 4% ! THAT is an EFFICIENT market!! And the group average price was $125 below the lowest 'NET' sale price and $225 below the lowest 'NET' regular 'retail discount' price.