You may find one or two of those spoon gouges useful inside the lock mortise, although my preference for, say the main spring area, would probably be a 5mm or 8mm, #5 or #7 sweep. I like to remove the bulk of the wood within an inlet with a gouge first, then smooth the surface, removing the ridge tops, with a chisel. I find the gouges faster and more forgiving than chisels for this. They also allow you to easily cut across the grain in tight spots.
Back to those spoon gouges, one other area they might be helpful, is the tail end of the trigger guard inlet where the grain is almost always working against you, although I can usually get by there cutting across the grain with a straight small shallow gouge. The deeper the inlet, the more likely the spoon gouge would help.
