Yes, AppleTalk was implemented over IR, so presumably this technology is the same thing.

I wonder if the external units were earlier than Apple's implementation or if they were later add-ons for folk who couldn't afford a new machine. If the former, then it wasn't invented by Apple but was possibly bought by the company, like so much else in the same era. That is not only true of hardware, but also of software — a good deal of System 7.5 has its roots in Shareware additions to 7.1.