Was there ever a System Install CD with System 6? I know the IIvx was the first Mac to have an internal CD-ROM drive and that shipped with 7.1, but externals were around since the IIx.

If there were no "extras" disks that shipped with these systems with custom applications and no CDs which might contain those extra goodies we came to expect from Apple, then I am hard pressed to know exactly how Apple distributed this mystery INIT, except by dealer only.