I tried it and the human/elf version of the staff can't be altered to make the gargish one. So I need to make the gargish version. Don't know why there are two versions of the staff if you can alter a normal gnarled staff to make a gargish gnarled staff.
Dr. spector lenses (from the same event) can be altered for a gargoyle without problems and the recipe is the normal one (human/elf). I asked this question because its too difficult to find some gear for a garg... and with the two versions of the carpentry recipe is even more difficult.