Correct - BB uses Snap instead of Hampton on its captoe (perf tip) oxfords, and on its captoe (straight tip) derbies. Alden equates the Snap last with the Hampton last. I own both and they are quite similar.
Either choice was a good one. You will enjoy them.FWIW, I have two bronze models, and I detect no greens. Had I detected greens, I would have returned them. While I don't have the mercer in bronze, the bronze is displayed quite well here:http://www.khakisofcarmel.com/product/edward-green-mercer-in-bronze-antique/