I think you do not understand what the term "Dutzendarbeit" means. This is a german term for a piece of workmanship that is not special, that is made "in dozens". So "Dutzendarbeit" is not a maker of violins or a school of making, but if someone refers to a violin as "Dutzendarbeit" he means that it is an instrument from mass production with limited but not necessarily no value.
So your question would really be: Can we deduce the production quality of a violin from certain elements of the carving, in this case the spine of the back of the pegbox.
My personal answer (but I am no expert) to this would be: To some extent. Obviously you’ll find the carving on a cheaply produced violin to be done with less effort than on a master’s work. If you look at the spine in the first picture you’ll see that it is carved much finer, and we do not see the scroll on the second one, but I think one would be able to see a difference in the carving. So my point is: Instead of looking for a single thing like a delta try to discern if the carve work is of high effort, if it has fine and clear lines and such. Even on instruments of highest value there can be a slight delta in such a spot.
Other thing to look out could be varnish, the general quality of the wood (is the back nicely figured?) and such.