"Argent", the name that the lady in the office texts, is the word for money in modern French, and in old French, "silver", derived from the latin argentum meaning "white money" or "silver". I consider this significant since the little monitor box that received the messages sent by the lady and Mr. C turns into a lump of silvery metal at the end of episode 5. It could also be in reference to the wealth of "the millionaire" who's referenced from the first two episodes and owns the glass box contraption. Maybe it is Jeffries who owns it since the call is relayed to Buenos Aires.
What about Argent(ina)?
Phillip Jeffries is in Argentina
Those are great observations! There's also a reference to silver with the Silver Mustang, so perhaps the casino may tie into this box scenario down the road as well. Precious metals and gems (silver, gold, jade) are definitely proving to be an important theme this season. However, I also noticed that another definition for 'argent' is 'the moon'. Argent is the word the woman texts, which seems to activate the box. Then, when making his cryptic phone call that seems to further activate the box and transform it, Doppelganger Cooper says, "the cow jumped over the moon." Of course, there might not be a deeper meaning to the argent/moon connection other than it being used as a code phrase to make sure the box changed. But who knows? Maybe the moon will have an important role later on in the series, just as Jupiter and Saturn did during the original run.
As a argentinean, I can't explain the emotion when I see the 9 de julio's Ave. (specially when the "Missing Pieces" scene of Buenos Aires was totally horrible -it's look more than a Mexico hotel instead of Bs.As.).
Hope the real Bowie wasn't dead and live as incognito in my city!
Might be interesting to note (although I have no idea if it has any relevance) that there is another reference of silver in this episode, namely Nevada as the Silver State (it's explicitly shown in one shot on some license plate).
I immediately thought
argent => silver => (Frank) Silva
I immediately thought
argent => silver => (Frank) Silva
(Ergo => Bob)
and don't forget that ARGENT is almost AGENT