Actually, you can. You can't checkout the code before that revision, since before then KoLmafia was in CVS, not SVN, and the CVS code repository is long gone. However, you can go to
Previous Releases on Sourceforge and find any release you want, back to Version 0.2 from Dec 24, 2004. Each version includes at least the source tree in a .tar.gz file and a compiled .jar file. Eventually, .dmg and .exe files were produced and uploaded.
KoLmafia-0.2.jar is a whole 69.6 kB. It has grown just a tad since then.
I first did CVS checkout of KoLmafia on May 13, 2005. holatuwol gave me commit access on May 20, 2005 and it's been all downhill for the project since then.
The first release containing code I submitted was presumably version 4.1 on May 23, 2005.
holatuwol imported it into SVN on April 3, 2006. Version 7.0 came out on April 10, 2006.
I don't recall how many thousands of commits went into CVS. Perhaps holatuwol saved the revision history somewhere.