Nothing that should be relevant to you if youre not Type Rated and they wanted to check your systems knowledge (if that was the case you wouldn't ask the question
). There are a number of different instrument combinations available though on the classics, there are some which are 100% steam gauge (except the TCAS IVSI) and some that are retrofitted with large LCDs, but usually you can expect the 1980s EFIS, a CRT PFD with a speed tape, an electromechanical ASI, IVSI and altimeter and a CRT ND. Engine instruments might be electromechanical or small LCDs, but that shouldn't matter for the purpose of a sim ride. Size wise, as you probably know, the 500 is the smallest and the 400 the largest model of the series, so even that shouldnt be a factor.