Yes, exactly. The automatic build mechanism gets the release tags from a "cvs ... log ..." command, checks out all releases and builds apms from that. So, the automatic build mechanism of the apm repositories depends on the CVS tag names (as defined in
https://openacs.org/doc/cvs-guidelines.html).
Yes, on a move to git, the apm rebuild code has to be redone (along with the cvs-guidelines, we need then git-guidelines, etc.). One could more or less translate the tagging rules, release guidelines and apm-rebuild mechanisms 1:1 into git (or for example, drop the apm mechanisms, i would not be in favor of that), but one has certainly to evaluate the tradeoff between effort and benefits carefully.