Regardless of the description, I'd consider that pipe a freehand, not really a dublin. Hard to know what the tobacco chamber would be shaped like since freehand pipes don't really follow the rules. I'd call the seller and ask a few questions if I was concerned about it.
And Missouri Meers do have tapered chambers. Every one I have, including the Mark Twain has a 14° included angle inside.. It must be how they hold them on the spindle to turn the outside of the bowl.