After the end of the Cold War and the fall of the wall, a lot of data came across about the the real readiness state of the Soviet military. Without going in to details to my reading it appears the Soviets were less capable of mounting an attack out of the barracks than NATO would have been in responding to such an attack.
Depends on which parts of the Soviet military your looking at and at what period of time. As has previously been noted, a lot changed in the respective militaries even within the 1980s. The forces in the GSVG, who would be chiefly responsible for executing the start of a bolt-from-the-blue attack, were generally held to much higher standards, and hence maintained a much higher readiness, then other forces in the Soviet military and could have reasonably been expected to be able to mount such an attempt with good odds of success in the early-80s, although reinforcement from the rest of the Soviet military would likely be slower then the Soviets are comfortable with (see below). That would mean the Soviets would essentially be gambling the entire war purely on the GSVG achieving decisive results, which is obviously an enormous risk. Soviet military readiness, as well as it's ability to increase it's readiness, also heavily correlates (with rather obvious casautive links) with the socio-economic "health" of the Soviet Union as a whole... something that was in constant decline during the 1980s. So the later one looks, naturally the worse Soviet readiness and mobilization potential appears.
Taking into consideration mobilization potential... well, from a purely geographic standpoint, the Soviet mobilization programs seem to have a clear advantage in vastly shorter LOCs that are overland and hence much easier to move formations over in a organized fashion and much harder to interdict. However, organizationally things are more favorable to the Allies in the 1980s. During the 40's, 50's, and 60's, the Soviets generally held to their WW2 methodology of recruitment and mobilization, which had proven tremendously able to rapidly mobilize and organize skilled military manpower even under massively disruptive circumstances. In 1967, however, the Soviets massively altered their manpower recruitment and mobilization system with things like increasing the number of annual call-ups while slashing the number of years that conscripts were expected to serve from three to two years*. The intent was to provide the greatest possible breadth of skilled military manpower, even if it required accepting some sacrifice in the "depth" of skills. However, this seems to have drastically and negatively affected mobilization speed and efficiency as when the Soviet's tested out their mobilization system for the calling up of reservists in the early-80s, the results were so catastrophically bad that even NATO intelligence noticed. Subsequent attempts to reform the system got caught up in the larger societal issues that the Soviets faced and ultimately sputtered out in the face of their socio-economic collapse.
The above actually means the Soviet armed forces would be much better suited to carrying out a "bolt-from-the-blue" attack in the 40's, 50's, or 60's rather then the 70's or 80's. Although maybe they could do so in the 70's pretty well, given that both the rot and NATO were much weaker then in the 80's.
*Not coincidentally, this is also what introduced the absolutely horrific hazing system which we know today as the "dedovshchina". While technically the phenomenon of new recruits being hazed by their seniors always existed within Russian/Soviet military system (as it does in practically all military systems) and always was know by the name of "Dedovshchina", there is no account of it existing in the specific form with which the term is associated today prior to 1967.