I don't think the bars & stem are a 'must' replace (unless of course they simply don't fit you...)- examine them carefully for cracks (and in the case of the bars, sagging), especially the top of the slot in the stem where the binding slug goes. If the slot is squared off, round it with a file/dremel/drill. If there are not signs of cracks or weakness, if it were me, I'd use it (and in fact I am, on my '72 PX-10), and just pull the stem and check it every now and then. $.02....