If by 'which X server' you mean the version:
tsinclai@homeg4:~$ dpkg -s xserver-xfree86
Package: xserver-xfree86
Status: install ok installed
Priority: optional
Section: x11
Installed-Size: 15628
Maintainer: Debian X Strike Force <debian-x@lists.debian.org>
Architecture: powerpc
Source: xfree86
Version: 4.3.0.dfsg.1-10
I'm already thinking I may have to hand-roll the config file, so I'm still searching.