[Dr. Deleto]

yes, the pk3 system picks up components in alphabetical order. Since the original game pk3 names start with "p" ex: "Pak0.pk3" you will want to name them starting with a letter that comes after p in the alphabet. This way it picks up your modified components after the original game components and uses them instead. The reason "z"'s are used so much is because they are the last letter in the alphabet and tend to always come last. Letter stacking also works here.

a file with 2 z's will come after a file with one z at the beginning of the name simply because the coding will pick it up after the single z'ed filename.

example in the order the moh engine would pick up 5 pk3's.

pak5.pk3
user-Myscope.pk3
Z-myblood.pk3
zsz-mycompass.pk3
zzs-mynewweaponmodel.pk3

hope this clears things up.