i would suggest no.
since the prefabs get loading into the map you are editing and only the map is required there would be no use keeping them around. however there are a number of unused stuff in the paks so douth thus....
1. copy the game pk3s to somewhere so you dont fuX0r the originals
2. change all the filenames to zip
3. goto a download dite and get into a file/disk/compression tools section... id recommend
http://www.webattack.com cause its got easy2use sections. get a program that searches within zips for files.
4. run a search inside all the pk3s for *.pfb (<--- that correct?)
OLE!
r3mix