Hello Spainflyer.... there is no 100% straight answer for you, since regardless of what the books say... restaurants sometimes deviate from the "theoretical" cuts.

Also... many so-called Argentine restaurants outside of Argentina many times have to serve non-Argentine beef, and also may not be able to source beef cut in the Argentine style..... its more complicated than one thinks.... may details involved, even if the restaurant imports Argentine meat or has a distributor it buys it from... chances are many of the traditional cuts are not available because many countries do not allow imports of beef with bones due to the lame foot&mouth excuse, etc. etc. etc. ---- again, the devil is in the details.

In the end... I dont really worry tooo much about what cut is called what... its about putting the chunk of flesh to the ultimate test (ie. eating it) that this is all about... but then again, Im a die hard carnivore so Im a bad example...