To get back to your original point, yes, having the original lid is better than not having a lid, or having an obvious not original one. Without the photos, I first thought the question had to do with a toy sized piece; because, I was thinking about the Griswold toy safety kettle, and of course, there were no photos. Seeing the piece you have now, the Red Book lists several Griswold full sized safety kettles. The range for price it gives is pretty wide, $75-$200. But I would certainly put your kettle in that range too.
Pricing odd pieces is tricky, if for no other reason than not many are seen. I’ve seen a different piece of iron sell on ebay for well over $100. There is a similar piece now on ebay. It has been listed three times, and that seller can’t even get $35 for the same piece. Go figure.