Fabrique Nationale does not have a plant in Argentina, and never did. Argentina did manufacture the FN FAL under license, and that was in 7.62x51, but it's doubtful you have an original military FAL. You'd need to give a make and model for this question to be answered.
Impossible to tell from just the serial number.
50-500 USD depending on specifics
Need a detailed description of all features, caliber, etc..
without a better description, 10-500 USD
Impossible to answer without the model of pistol,caliber,overall condition,and a serial number to date the firearms production year.
Need a detailed description of all features, caliber, finish, sights, stock/grips, etc..
There is no way of answering this question without a serial number included in your question.
No serial number given.
No way to know the caliber from just the serial number
Serial numbers do not designate calibers. Look on the brrel to ID the caliber.
Can't tell the caliber from just the serial number.
You will have to call FN and provide the serial number.