I would suspect the Chambers Queen Anne Pistol lock will be too small with your barrel, both visually and not enough space between the pan and top of the mainspring to allow you to place it correctly on the stock.
Also - keep in mind on these locks - the plate length is one thing, but they also all differ on spacing from the pan to the sear, which affects your trigger placement and wrist-comb architecture and pull if the gun is already cut for pull length.
The Chambers Early Ketland and the Twigg are longer in this distance than the Large Siler.
The large Siler, Dale Johnson, Chambers late Ketland, and Durs Egg are all about the same size in this distance.