Pretty much all of these types of weapons don't do any additional frost damage or other school of damage, only physical. I've tested this multiple times in prep for Нечистотон
in AQ40 with iceblade hacker, I did have the frost bolt proc weapons prior to that and they work fine.
This means you don't get frost dmg added to a weapon that states it does additional frost damage.
I do remember a bug back in Wotlk with an axe from Storm Peaks rep that caused multiple embue's to proc twice which these weapons may of been effected during the hotfix during 3.0.3
item: brunnhildar axe
These are the weapons i've tested so far with no additional frost damage outside of the proc itself there's no base +5 frost damage.
item: iceblade hacker
item: warblade of caer darrow
item: cobalt crusher