Chris responded to my inquiry at the m0n0wall forums that m0n0wall uses IPF 3.x on 1.2x and IPF 4 on 1.3x. I was wondering because I'd like to use a load balancer on m0n0wall.
Based upon that information, I found pen:
Chris also responded to my inquiry about config backups with a link to the manual:
This is a great script to backup config files to a CVS repository. Since I use subversion, I'll modify it and post it back to the mailing list. In fact, I'll probably setup something similar for several of our servers, since I already store the config files for each machine in subversion! :-)