I say mass-produced, through a series of open die forging. One operation to make the initial "blank" (which would encompass the tang and bridge along with necessary metal for the tines), next would form it into an elongated form, then next would split out each tine, and last would form the final profile, bend of tines, point of tines, etc. Could be one man, using several stations so as not to lose heat, or more than one man with any combination of steps thereof.
Just my .02, take it for what it's worth. I'm not an expert. But I have dabbled in blacksmithing as a hobby for several years now.
Just thinking through the steps for a blacksmith to make such a tool, I don't think it would be worth his while to undertake such a job, between the forging of the initial blank, splitting of the blank, drawing out of that many tines, and the finish work to achieve that level of symmetry. The cost for the tool would be rather hefty back in the day, I would think.
A smaller 3 or 4 tine fork would probably be more common to find handmade, but still wouldn't have that level of finish work and/or symmetry.
