The numerical
Grades were used in the factory. The letter
Qualities were used at the retail level.
However, by the 1920s terminology was in flux. In the 1925 catalog Parker Bros. uses
Quality some places,
Grade other places with the letter designations, and many places just the letter designations. In the 1927, 1929 and 1930 catalogs I have the guns are listed as
PARKER B.H.E.,
PARKER TROJAN, etc.
January 1, 1930, Parker G.H.E - Parker G.H.jpeg
By the Remington era they were using the term
Grade with the letter designations.