Transparent scheduling of superscalar execution was a later advance in microprocessors, termed out of order execution. Apart from micros both did come out around the same time in the mid-1960s.
In the x86 microarchitectures superscalar came in Pentium and OoO got introduced in Pentium Pro.
(Superscalar is just having >1 pipelines, which at its introduction meant needing to manually schedule your code very carefully to take advantage of it absent the OoO execution. For example the frequently posted-about Doom optimizations and talk of the u and v pipes are about this. The scheduling didn't happen transparently in early superscalars, at best the cpu automatically stalled, and some archs (eg MIPS, i860, TI C3x) even visibly punted hardware detection of pipeline hazards and required the code to just not go there, see load delay slots and branch delay slots.
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I'd argue most people would consider it scheduling only if there's some attempt to arrange order of execution to improve throughput. Idling the other execution units when they could be executing instructions is not scheduling, at least not good scheduling.
In estabilished computer architecture terminology, scheduling is decidedly a OoO execution term. (At least if you're talking about processors. There's also static scheduling, which means the compiler does it and the hardware doesn't.)
In the x86 microarchitectures superscalar came in Pentium and OoO got introduced in Pentium Pro.
(Superscalar is just having >1 pipelines, which at its introduction meant needing to manually schedule your code very carefully to take advantage of it absent the OoO execution. For example the frequently posted-about Doom optimizations and talk of the u and v pipes are about this. The scheduling didn't happen transparently in early superscalars, at best the cpu automatically stalled, and some archs (eg MIPS, i860, TI C3x) even visibly punted hardware detection of pipeline hazards and required the code to just not go there, see load delay slots and branch delay slots. )