Early double stabilizer grind??

My understanding is the hollow grinds with a double stabilizer heel did not start to show up until the 1870's. B. J. Eyre & Co. used the Late Greaves stamp for only a few years after they acquired the Greaves company. That would put this blade/grind about 20 years earlier. Many blades were professionally reground later in their life but I do not recall ever seeing a reground blade with the show face etched. An interesting razor.
Any thoughts?
Attachment 268294

Old Tang stamped blank found and used at a later date

KISS