We have AZone here too...
We also have a local NW chain for auto parts here as well. "I am sorry sir , but the computer program only goes back to "1969"... I can only go back to 1969...
that is what I was told by one of the "experts" once. Tell you what a kid, lets take a risk & keep our fingers crossed that the 180 thermostat will work on the "1968" too... I will keep my reciept... LOL.