replacing 62 year old 3 way switches
Well that is close but today the common screw is one color and the other travelers are the same but different color. The store's advice can be right but I have also run into this on switches that were not labeled or color coded. The good thing is it won't hurt anything if the 3 wires are mixed up. If they don't work correctly you can try moving the wires to different screws 2 at a time only a few trys at worst case and it will work correctly I have had to do this for friends that messed up switches and over for dinner was asked for help with no meters or testers and just a screwdriver.