Austin,
Yes, the very first Kirby Traditions did have their speed switch inside the headlight, which had a lock lever on the outside.
On these, the motor would not run until the headlight cap was all the way down toward the nozzle, hose, Miracle Head or Handi-Butler, as well as being locked into place. This kind of speed switch, installed near the headlight lens, was problematic in that some users would jam the headlight cap toward the nozzle or hose, causing the speed switch internals to fail to the point where the motor would run on high speed all the time.
Afterward, Kirby then put the speed switch back on the fan case. But the headlight cap still had the lock on it. The speed switch also had this blue rubber dust cover to protect it from moisture generated by the use of the Rug Renovator--the original intent of the speed switch being mounted to the underside of the headlight cap. Yet even that presented problems for the speed switch... dust would sometimes jam it, again causing the motor to run on high speed all the time.
Then Kirby ditches both the locking mechanism for the headlight cap and the dust cover for the speed switch... and the rest is history for this model. Kirby subsequently issued advisories to modify cleaners built with the speed switch on the headlight so the switch is on the fan case; and on those units built with the dust cover over the speed switch, to remove the dust cover.
~Ben