A question about insignia.

I think I am confused with insignia.
I will take my mesmer that was created in the first campagin for example.
I bought the enchanter armor for this mesmer in Droknar's Forge.
I am not sure if this piece of armor = Armor crafted in Elona with Radiant insigna in it.
If yes, does it mean the player can add another two individual insignia into that Elona armor since it got 3 bonus from the Radiant only?
For instant, the armor can ends up with Radiant + Virtuoso + Artificer in it, which characters from Cantha or Tyria ara not allow to do. Does it sound unfair?

Sorry if it is messy, I have tried my best to explain what I want to ask...
Heehee...

You can only apply one insignia per piece of armor.