>in 2006 was still using svn
Perhaps you meant cvs? Subversion was released in 2004 and git appeared in 2005.
We used cvs, but did switch to svn before/around 2006, but I could be mixing that up. We did not switch to git even by 2012 when I left.
The reference to the 70s and 80s code didn’t imply it was version controlled before svn/cvs though if that’s what you meant, but by that time it was and still had old timestamps commented in the text files.
Subversion 1.0 was released in 2004, but it was already widely used before then.