extracting original git commits from "git svn" repository?

About two years ago, I started an SVN repo for a private project.
After a few months, I started using "git svn" for day-to-day updating
(to take advantage of offline commits, etc).  git-svn has been
fantastic, but since it doesn't maintain AuthorDate (or, if it does, I
don't know how to ask it to do so), I'd like to migrate that SVN repo
to a git repo.

Is there any straightforward way to recover the "original" git commits
(spread out across two different workstations), so I can reinstate the
proper AuthorDate information?

Does this request even make sense?

I can have all the original data in one place, and I've got plenty of
CPU and RAM to throw at the problem:

  server.svn/...
  workstation1.git/...
  workstation2.git/...

I'm hoping that it can be done with sufficient trawling through the
reflog, but I thought I'd ask before trying to do the conversion
myself.

Thanks in advance,
Tony