[PzLdr]

I beleive the tank in “Sahara” was a Grant. 37mm in the turret, 75mm on the hull in a sponson with very limited traverse. The M3 Stuart was a true light tank, with only a 37 mm gun, and almost no armor [made a hell of a comic bnook though]. Germans ate ‘em for breakfast.

[Talisker]

I beleive the tank in “Sahara” was a Grant. 37mm in the turret, 75mm on the hull in a sponson with very limited traverse.

Good catch. You can see the 75mm in the right of the photograph.
Fourth Armored Division officers and members of the Hollywood crew, in the Mojave Desert in 1943, for the shooting of the wartime movie, "Sahara." Humphrey Bogart kneels at left.

An interesting article about the making of the film, written by a Fourth Armored Division officer in the photo, is here. Although at the end of the article he refers to "Bogie’s Sherman tank," given what you observed he must just have been writing for a general audience.