If it's a .aiscript file for se_mitchelldown_v2, then it is serious. If it is just a .script file that isn't there, then you don't need one. Only certain maps that we needed to alter the default map scripts will have a .script file with them.
RTCW will read in information in a sequential basis from the pk3's. Starting from fritz0.pk3. So if there are duplicate files in files that come in a file like fritzDenny.pk3 or fritzCrapshoot.pk3, it will use those instead. So the short answer is no, it doesn't matter if there are duplicates.
With the next patch that is released, all of the latest waypoints should be in a single fritz0.pk3. Using the other pk3 files is a way for us to release new map waypoints without the user having to unpack and repack the single pk3 file with new waypoints.
The fritzCrapShoot.pk3 is an alternate defense for those two maps. They will give up certain objectives in order to defend the main objective better from the start. It was debated quite a bit while beta testing and releasing on if they should do this or not. I preferred that they do, but in the spirit of the mod being geared towards public play, I made them play a bit more "unorganized". Basically they are there to try out. If you like them, you can keep the pk3 file there, and if you don't you can simply remove it. There won't be any issues with duplicates as stated above.
PowerDam was submitted by Craig in this thread.
http://forums.bots-united.com/showthread.php?t=4665
i'll get his waypoints uploaded to the waypoint repository within a day or two.