And I assume also that the reason to build 2 identical prototypes was mainly to respect this principle of fair and equal share between the 2 countries; am I right?
To use a well known French technical response: "Oui, mais..."
Partly out of equal shares, but there was also more flight test development work than could be handled by just one aircraft in a reasonable timescale, and each partner had their own sphere of responsibility to cover so if you have to have two airframes it made some sense to have one each.