Quote History Quoted:
Do you have a picture of these early 601 doors? ? I'm trying to visualize these. Would like to learn more too.
Jon
View Quote
The primary indicator of the early doors is the flat square "pad."
However, there is a difference between an "early" early door and a "later" early door. The earliest doors have a "round" detent housing...
...while later "square pad" doors had the "angled" detent housing like the rectangular pad doors.
Based on the several samples I have on hand, the detents are all held in place by roll pins.
Unfortunately, I don't know when the change from round to angled detent housings happened. The "later" square pad door shown loose above may have come off a 602.