Firstly, credit should be given where due so I apologize for not remembering where I got this info/pix … I note also that you are writing from S.America so you may have a right hand drive vehicle in which case I assume the holes may be reversed!!!
The first picture shows the passenger side of two of the frames, showing that the only differences come as a result of the type of mirror mounting - one has a clamp on type and the other 2 have holes drilled through the frame for a bolt on mirror bracket. I believe the C/L indicates the 'CenterLine' (middle) of the frame.
The 2nd pix shows the mid portion of the frame and the two different styles of mirrors.
The 3rd pix shows the driver's side, where all three are significantly different. The top frame had a hand operated wiper, and I've been told that the bottom had an electric wiper motor. Not sure about the hole configuration in the middle frame. On the engine side of this frame all of the mystery holes are 5/16", while on the interior side the two outside holes are only 1/4". Basically, i would disregard the middle frame!
Incidentally, the middle or mystery frame is the only one of the three to have finger pulls on the interior side. The early frame did not have pulls. Hope this helps.
