If I understand your question correctly el @, you are asking whether a pilot flying his own airplane to say, Argentina, would require an Argentinian validation.
The answer is "no", since he would have a licence from his country, and is flying an aircraft registered in that same country (example, a pilot with a US FAA Pilot Certificate flying an "N" registered airplane). Legally, he is allowed to operate this aircraft anywhere in the world, including Argentina.
The requirement to get an Argentinian licence validation is if he wants to fly an Argentinian registered aircraft.
In a way, silly, and in fact fact I understand that ICAO recommendations are that all ICAO states accept foreign pilot licences at face value, however I don't know of any ICAO state that does.