In 13th age, most effects that add damage to an attack specify that they either add damage on a successful attack:
Building Frenzy (Barbarian)
One battle per day, as a free action after you have missed an attack, gain +1d4 damage to each successful melee attack until the end of the battle. For each missed attack following this, add another +1d4 damage, up to a maximum of +4d4 damage.
Or add damage even on a miss:
Heavy Blows (Fighter)
You gain a bonus to your miss damage with that attack equal to the escalation die.
Unfortunately, magic weapons and implements seem to be the only place where this pattern is broken, stating they simply add a tier appropriate amount of damage on an attack with the weapon. I didn't even considering adding the bonus to miss damage: partially from experience with other systems where miss damage is non-existent, but mostly because the Miss lines on attack with miss damage states
Miss: Damage equal to your level (Emphasis mine)
So, should a True Magic (or Rune'd) Weapon or Implement add its bonus damage to Miss Damage?