Launchbury will be joined on the sidelines by Malakai Fekitoa after the All Blacks centre was slapped with a one-week suspension for a dangerous tackle during last Saturday's incident-packed test against Ireland.
"Every coach in the land is aware of the consequences if you have contact with the head. There has been a specific focus brought to this aspect of the game," former flanker Gustard told British media.
"But I don't think anyone has ever coached tackling around the head. We're certainly not doing that... We had a meeting about it and players have had meetings at their clubs.
"Our focus in the tackle is to put people to the floor. We're not coaching foul play or illegal play. We try to coach good technique that will stand up under duress and fatigue."
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England, on a 12-match winning streak, have conceded five tries in their two November international games so far and Gustard said it was essential the Pumas should be given no easy points.
"We've spoken as a group of the need to raise our level again," Gustard said.
"We know there's a big threat there with Argentina ... they will be coming for us because frailties were exposed and it's an area of strength for them."
Semesa Rokoduguni was surprisingly left out of the England squad to play Argentina on Saturday, despite his man-of-the match display against Fiji. Gustard, however, defended the decision to drop the Bath winger.
"On a game-by-game-by-game basis we have to pick a team we think is most appropriate for the threats we are going to face and for the opportunities we want to exploit," he added.
(Reporting by Shravanth Vijayakumar in Bengaluru, editing by Nick Mulvenney)
