Up until the Mid 70's aircraft also had Light Aircraft Grey Undersides.But the wrap around scheme that LD mentioned only applies to tactical aircraft, harriers, Tornado's etc. Other types, such as Phantoms, retained the lighter undrside.
So depends on aircraft type and which part of the 70's.
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On the bench: Airfix 1/72nd Harrier GR.3/Fujimi 1/72nd Ju 87D-3