Just went through some of my old catalogs to verify my memory and the case-colored v. enamel works out like this

Fox B-DE Fox B-ST Fox B-SE Fox B Fox BE Stevens 311 Stevens 311R Savage 550
1961 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1962 Satin Chrome Finish
with Decoration		 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1963 Satin Chrome Finish
with Decoration		 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1964 Satin Chrome Finish
with Decoration		 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1965 Satin Chrome Finish
with Decoration		 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1966 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1967 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1968 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1969 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1970 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1971 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened Case Hardened
with Decoration
1972 Black Satin Enamel
with Decoration		 Case Hardened
with Decoration		 Case Hardened Case Hardened
with Decoration
1973 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened Case Hardened
with Decoration
1974 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1975 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1976 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1977 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1978 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1979 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1980 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1981 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1982 Case Hardened
with Decoration		 Case Hardened
with Decoration		 Case Hardened
1983 Case Hardened
with Decoration		 Case Hardened
1984 Case Hardened
with Decoration		 Case Hardened Case Hardened
1985 Black Satin Enamel
with Decoration		 Black Satin Enamel Black Satin Enamel
1986 Black Satin Enamel
with Decoration		 Black Satin Enamel Black Satin Enamel
1987 Black Satin Enamel
with Decoration		 Black Satin Enamel Black Satin Enamel

Fox B = Double triggers, no ejectors
Fox BE = Same as Fox B but with automatic ejectors.
Fox B-ST = single trigger, no ejectors
Fox B-SE = single trigger, automatic ejectors
Fox B-DE = single trigger, no ejectors
Stevens 311 = Double triggers, no ejectors
Stevens 311R = Double triggers, no ejectors, 18.5" barrels
Savage 550 = automatic selective ejectors, single trigger, top-tang safety.

Starting in 1979 Savage stopped specifying what the action finish was in their specifications table so I had to go off the photo's in the catalog. In 1985 it appears they stopped case hardening the actions and went back to a black enamel finish.