I also forgot to mention that I have found there was a mid production change with the 4wd trucks as well (not well known) which may only be a 1/2 ton thing as that is where I have encountered it so far. I have both versions, to easily tell the difference look at your front cab mounts if you have the ones that extend to the outer edge of the cab floor it is an early style chasis and if the front brackets are only 4 inches or so then it is a later style chasis. For some reason gm used different park brake cable leingths nearly every year on their K trucks.... btw does your truck have the deluxe style rear cab mounts?