There are 6 styles in the Westclox Bull's Eye Watch Pocket Watch Style Series
Oval bow, oval pendant.
1929 - 1931
Oval bow, retangular cutout pendant.
1931 - 1933
Oval bow, flat tapered pendent spaced slightly away from case. Various non-luminous dials and black luminous dial.
1933 - 1936 and 1938 - 1941
Oval bow, white dial. Has seconds bit through 1975.
1957 - 1979+
Short trapezoidal bow, white dial, no seconds bit.
Starting in the early 1980s?