That is a pretty weird position. So no Argentinians ever visited the Falklands by getting their passports stamped by the British in all those 150 years? I find that quite difficult to believe. The Argentinians provoked the conflict, the British simply insisted on normal protocol.
Even weirder. The "scrap dealers" went nowhere near the Falklands. But they refused to get their passports stamped on entry to South Georgia, an island not part of the Falklands/ and never visited/claimed/settled by the Viceroyalty of the Rio de la Plata(Spanish) or the United Provinces of the River Plate(Argentine) in the 19th century.
It was that raising of the Argentine flag on South Georgia combined with the refusal to submit to entry provisions which was a clear declaration of occupation of undistputed British territory.