Look at the label. If it lists THCA in higher levels than THC, you'll need to decarb to activate the THCA(acid) into THC.
In most cases, due to the way wax, shatter, oil, etc,.. are processed the THCA remains unactivated so there will be no psychoactive effects until the THCA is heated and converted to THC.
The oil in the cart is concentrated, so it may be stronger than you think. A little may go a long way once decarbed.