The vent windows are the same for all three years. That "extra" metal looks like someone welded in the handling tabs that are on some parts from the stamping operation.
no they arent. there is deffinitely a difference in 67-69. i found this out the hard way after my car was apinted and buffed out. i drilled out the spotwelds, switched the vent window brackets around as my 69 were the nicest i had and they were complete. you will also run into issues with the lock and inside handle hardware. i know. check the location of the inside door lock hole and the location of the side view mirror. those will give you more of an idea on the year. i think both were changed for 69. the lock moved foward, the mirror moved back.