You have to check the files by yourself and see if Dell has added anything, If nLite editted these files, it most probably added to whatever Dell had already done (that's an IF), you can try and change the PID, then see if it works. You probably will see Dell's support info when viewing System properties, these could be altered or removed easily. We can't see your CD, if it was made (burned) by Dell you should be able to tell, if it looks like an Original XP CD, you don't need to worry about non of the above except the PID!
The PID for OEM CDs has letters OEM instead of numbers, all you need to do is to delete OEM and type 270 over it, this tells the setup to accept VLM keys.
If you are not sure, just use any XP Pro CD (original) slipstream SP3 and any hotfixes you want, edit the PID and burn yourself a CD.
I have a HP XP MCE DVD that when I use it on HP systems, don't even ask for a product key, but when I use it on other systems, I have to enter a product key. This shows that they can have setup retrieve information from the CMOS.
If after changing PID and doing a test install, you experience problems, we can look in to the files for you if you wanted too, as long as you don't post your key and important information if any with them files!.
Some CDs that have been editted with the OEM's information might also contain "sysprep" folder and an "unattend.txt" file but usually this file needs to be renamed to "winnt.sif"
The OEM, Retail, Corporate, VLM, Special Student (forgot what is called) CDs all have the same i386 folder which is of most importance but the PID tells the setup what keys to accept.