Lee Tank with Side Skirts

The US Army did use at least one M3 Lee tank with sand shields.

The British Army also used them in North Africa alongside their Grant tanks.

The Lee tank was in production and there was a short delay until the Grant version could be produced and shipped.

The US Army intended these tanks would only be used in training to get troops used to the 75mm gun.

The blueprints were based in part on a self-propelled experimental gun that was not adopted for service.  Using those blueprints sped up production of the Lee.

The US Army wanted this medium length 75mm gun to counter the short 75mm gun on the early Panzaer IV used in France in 1940.