Sadly you have to figure out if said attachments actually benefit the weapon it's on. As they don't all produce the same effect on each weapon that has an option for them.
At least according to driftor and he's pretty reliable. Like High Cal is (and almost always has been) nearly useless on everyweapon that lets you equip it (Or whatever increased headshot damage variant it is in other games) because the multiplier for individual weapons or weapon classes can be so incredibly low.
In MP terms for example silencers aren't worth it on most weapons (Pros to cons)
However the swordfish is arguably one of the best weapons to use it on because with or without a silencer even with the Op Mod...it's still taking a little over 5 bullets to kill (even if you hit all 5 shots and 1 is a headshot). So you can actuall get away with using a silencer on it.