If the original develoeprs had used Git, they'd be mostly fast-forward merges. Those are the default merge operation in Git, and they don't appear as merge commits in a repo.

However, there commits start 33 years before Git was created. Merge commits were not even a concept back than.

I don't think either SCCS or RCS tracked merges, so everything looks like a new revision.

What did source control look like 30 years ago? Was merges used a lot? I have only used Subversion and Git.