Dave,
In 1913 Smith started using the Curtis push button release because of complaints of forend falling off and getting lost. So Hunter Arms started using this fastener on their non ejector guns. Stopped around 1919 (Brophy stated patent infrigment), truth is it cost to much to make.
So after this date all guns from Ideal Grade up without ejectors were given the banjo style until around 1936 and then went to the retangular shaped one.
All Field Grades non ejector were left with just the "J" spring and electrical tape to hold it on.
