My own thinking was: there was more than one Dumoulin maker, some higher end than others. Chances of my asking and hearing back in time from this kind of auction house seemed unpromising.
The gun's weight is unspecified. The bore condition also unknown. The exterior looks good. I thought the wood was of superior quality, but the level of engraving was not very high. I doubted very much that it had ejectors. It would almost certainly be a short-chambered 16 gauge.
There is obviously no big Dumoulin collecting market in America. There might be in Europe.
Still, an over-and-under hammer gun, especially with a side-lever is pretty darn cool. I thought it might very well go cheap, and even if it was a boat anchor, it was an interesting gun, so I bid up to around $1000.
Obviously, somebody was keener than I was.