Jump Seat FAQ:

There are 6 total different jump seats.
#1 - 1963 - 1969, long style with 2 bolt holes per a leg
#2 - 1970 - 1973, long style with 1 bolt hole per a leg.
#3 - 1973 - 1975, Short style for roll bar, bad tendency to brake at joints.
#4 - 1976 - 1977, Short style, for roll bar, slightly better bumper design. Still breaks easily
#5 - 1978, short style, excellent for all earlier years, black and has a fold down support leg.
#6 - 1979-1981, short style, It is a bit updated from the 78 style. Steel bottom plate is at edge instead of inset.
#7 - 1982-1985 short style, updated and a smaller fold down leg.