If you still have an old PRCS repository, it could help you converting a PRCS project to a Mercurial (or Git) repository by the Mercurial Convert extension. Feel free to make a feedback if it looks interesting.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I am writing a new extension for Mercurial that adds PRCS as a source of the Convert extension: http://mercurial.selenic.com/wiki/ConvertPrcsExtension
If you still have an old PRCS repository, it could help you converting a PRCS project to a Mercurial (or Git) repository by the Mercurial Convert extension. Feel free to make a feedback if it looks interesting.