Verifying Low E & Argon
A flame placed near the glass, (not too close), will show the reflections of the flame in the glass.
You should see a green tint in one of the reflections, (I think it will be the third one.), and that will be the low-E.
Argon gas will go away all on its own! It just happens.
How old are your windows?
I grew up in the window business and I have been told by every manufacturer I've ever delt with that the argon will last about 5 years or so before it disapates.
Loss of the Argon fill may reduce your insulative value slightly but not enough to worry about. It's just that Argon is a little more efficient than a pure vacumn. It's somewhjat of a sales gimmick in the quest for the holy grail of the perfect window, whioch doesn't exist, IMO.