Ryan, By the mid 1860's it seems that the Brits had figured out about everything one could do to a lock. Actually the tumbler and other parts are quite normal in size, however the cut for the fly and the fly itself are oversize. A relative lot of material/mass removed from the tumbler in this method but their locks seemed to withstand OK.
Rob, the trigger plate extension is the conventional pineapple and fan. A little engraving is planned to bring up the details here and just border engraving on the lock.
