Yes, the Diamond Edge knives went thru quite a few changes over the years. They were initially a step up from the old Jackmaster line. Well... until production was shifted to the Ireland plant. Then they cheapened them considerably, mostly using co-molded handles.
The trademark was used by Shapliegh Hardware until 1960, then by Val-Test until '65. Imperial seems to have started using it in 1967 if Goins is correct.
Codger