67' Cab Question (kinda long)

[6772owner]

Ok guys I searched the threads and cant really find the answer I was looking for..... I want to know if its possible to identify what year a cab is. Let me explain a little better, I bought a 67' K10 pickup before I knew of this forum and was only modertly educated in the 67-72's, after being a part of this forum im on the path to much knowledge, anyway the truck has a 67' front end (doesnt mean much) the cab has the small rear window, but it also has a dome light and the vent on the drivers side door pillar. I assume these were just added to teh cab for some reason (damn PO's) what do you guys think? The cab doesnt have the ID tag on the glove box door, I only have the VIN to go on (I assume that is worthless for this question). Any other ID points? Thanks