It certainly helped. Using the IPSOS-MORI polls as evidence, we see that Labour had a lead over the Tories in every poll after the 1979 election. The Tories moved into the lead after the Argentinian invasion and never fell behind again. (https://www.ipsos-mori.com/researchpublications/researcharchive/2449/Voting-Intentions-in-Great-Britain-19761987.aspx#1981)

However, there is a danger of the post hoc ergo propter hoc fallacy here (after this therefore because of this). Thatcher faced a divided opposition following the split in the Labour party and formation of the SDP. Labour ran on a radically left wing platform which alienated many voters. Also, after a severe recession caused by her policies, Thatcher had in fact changed tack (contrary to her rhetoric) and the economy was improving. Only the Mirror supported Labour. The Guardian backed the SDP-Liberal Alliance. Every other paper supported the Tories. It should be said that this was not unusual (see the table here http://www.theguardian.com/news/datablog/2010/may/04/general-election-newspaper-support). The Sun switched to the Tories after it was taken over by Rupert Murdoch.

It is often forgotten that Thatcher was not especially popular. Her average satisfaction rate was 40% (-14% net). Even the Falklands War only pushed this up to 54% although it did improve people's views of Thatcher's leadership and competence. In the 1983 election despite facing a divided opposition, the Conservative party won 44% down 1% on 1979. This produced a huge majority due to the British electoral system (the Alliance won 25.4% but only 23 seats). Labour won 26.7%, a traumatic defeat. Had the opposition vote been unified or had Britain a proportional system, Thatcher would have lost.