When I did hub replaces I found that the API (via the CLI) reported the channel the driver was last installed from so that information was still there, but as you say the channel enrollments weren’t carried over. This seemed to be a concern as channels appear to be key to the driver update mechanism and indeed unenrolling from the channel is (or was) a known way of preventing your driver being updated.
The default channel doesn’t require enrollment so the problem is mostly limited to those with community or beta drivers.