The pk3 DOES need to be edited slightly.
Rename it to .zip, then open it up and get to the point where you can see the folder named "saber".
Then, rename the folder to "saber_whatever". Whatever should be the name of the hilt.
Then, zip it all back up, rename it to .pk3, and then place it in your gamedata/base folder.
The Man's Prayer:
"I'm a man, but I can change, if I have to, I guess..."