assuming that the +2% crit chance is inherit from the anti-proton weapon itself, there are only two modifiers on the antiproton weapons from the PvE daily quests; compared to the antiprotons from the PvP daily quests which have three modifiers. If the +2% crit chance is NOT the inherit trait from anti-proton weapons then the PvP daily quests would have FOUR modifiers. (both break the rarity conventions since green=1, blue=2, purple=3)
this used to be the case for both ground and space weapons, but in an unnamed patch they rebuffed ground weapons so that they are identical. PvE and PvP shields/deflectors/engines have an equal number of modifiers exept differently split.