I'm not sure spinning the prop on a free turbine engine will do anything for you as the power section is not turning. As someone mentioned earlier, cranking for a longer period of time prior to adding fuel can cool down the temp if it is still warm although if using battery only, you are depleting the battery. Based on a totally different engine I am operating these days, prior to lightoff, the measured temperature definitely decreases during the initial cranking for a warm engine and increases a bit on a cool engine.