Marking (Greenblatt Version) :
See Picture G
The Eye is made of Glass with 2 wires embeded in it
These 2 wires are inserted thru a hole in the cast iron
and floded over to secure the eye in place on the doorstop.
Note 2:   CAUTION   Missing
Usually found without its Glass Eye
Note 3:   CAUTION   Bookends
Bookends exist that look exactly the same as the Doorstop
except the for the size : 7 1/2 " tall by 6 " wide
They are marked : 39 --   See Pictures E & N.
The Bookend version does not have a glass eye. See Picture D
National sold this doorstop unpainted for 30 cents or
electroplated with brass, copper, or nickel for $1.20
per National's 1920's Catalog.