Does kdm get display properties from outside XF86config?

All;

This may be a common one, but didn't see any current postings.
When I upgraded recently from a regular 19" CRT to a flat panel
LCD I hit one weird quirk during system startup.

The flat panel is a Philips 19" and I'm running Slackware 10.

If I boot to run level 4 to auto start X then the Philips panel
complains that sync is out of range. Especially the vertical sync
which must be 60Hz.

I've edited the XF86config file that I had from previous versions as
well as the xorg.conf file to give the monitor a range of 60Hz only.

But, and this is why I ask the question, if I boot to text mode,
run level 3, then start kdm manually - everything is fine.

Any suggestions?

Thanks in advance.

Jeff