MARKING STYLE :
They put their name:   EASTERN SPECIALTY MFG CO in Typewritten Block Style
Sometimes, they added the name and number of the Doorstop.
All this Lettering & Numbers were on a slightly raised flat surface above that of the doorstop back.
Their Noted Doorstops:
OWL on BOOKS
MAYFLOWER - the SHIP
HORSE JUMPING FENCE
LARGE OLD SALT