Granted that old/gen7 is not currently a valid URL but we can know
that, 5 or 10 years from now, when Linux-libre has moved on to the 8th,
9th or even 10th generation, the 7th generation scripts will exist
there. If Guix can begin checking those additional locations now then,
in the future once the current Guix version becomes an old version,
hopefully it can transparently handle that transition without issue. Or
just use git. :)

Even this method is just a band-aid though and has a different set of
challenges for the long-term. I'd be happy to discuss that with whoever
is interested.