Don't be too surprised by the lack of replies. If you can't find similar completed auctions on ebay, I can assure you there is no magic database here. And I'm not trying to be facetious.
The often quoted "Yellow Book" does state that while these are rare pans, the collecting community does not appear to have much love for them because they are completely unmarked.
How can you put a current price on speculation? Even the best GF Filley gems pans are bringing less than $300 these days. The Griswold Loaf Pan (without a lid) sells for half of what it used to.
There are many pans made with slight variations to the pan posted here. Some are extremely well cast, but trying to get $150 for one nowadays would be tough if you ask me.
Keep in mind that I don't collect Griswold directly, but I do watch the selling price of many gem/bread/muffin pans.