This I believe to be true. There was quite a bit of talk back then in the Army to be possibly prepared for action if the USSR invaded Poland and few of us believed Reagan was joking or bluffing.
I think tha the Soviets were planning a bit more than Poland, i.e., march west from the InterGerman border. Do a check on Colonel Kuklinski, a Polish army officer who leaked the Warsaw Pact warplan to the CIA. The balloon was about to go up.