You are right. If it has been working OK, no signs of heating, I wouldn't screw with it. Tell the buyer you will buy new devices but he has to replace them after the sale closes. Then it is his problem. I think the aluminum wire thing was over hyped. If your 1967 house hasn't burned down yet and you have no trouble signs, it is OK. Messing with can only make it worse. I would address any devices that do show signs of heating but you have to mess with it to see. That old 1350 alloy wire doesn't like being bent much and it will break. That is just my opinion but I had an "aluminum" 1971 house and my ex still lives there trouble free.