Use GitHub Classroom with GitHub Enterprise Server (on-prem)?

My institution is currently in the process of applying for the Campus Program. We have a trial license for GitHub Enterprise Server (on-prem), and I’m working my way through the Campus Advisor training repo. I’m confused about how GitHub Classroom fits in. I’m not seeing a way of hooking it up to an instance of GHE Server (or anything other than cloud GitHub). Is this correct? Some googling has lead me to

(Also education/classroom#240 – I apparently can’t put more than two links in a post).

From this, I’m surmizing that at some point in the past, GitHub Classroom was an open-source project that you could run yourself, and support was added for it to be usable against a GHE installation. That repo is archived and indicates that GitHub Classroom is no longer open-source.

Am I reading this correctly that GitHub Classroom isn’t usable with on-prem GitHub Enterprise?