My impression is that everyone here is correct. There are two different types of rear view mirrors.
However, it appears as though Toyota had 2 different vendors throughout the production of the Mk II. I think that it is more or less luck of the draw as to which one you got.
I thought that I would post this so you can identify which mirror you got and which internals you will need without having to take the mirrors apart.
The two companies are Murakami and Tokai Rika.
The interior adjusting mechanisms are totally different, and the exterior shells differ in having the mounting screw on the bottom of the shell.
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Toyodiy.com listing of Rear View Mirrors showing both vendors were used throughout the Mk II lifetime
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Note the Murakami logo highlighted in Green
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Murakami Mirror Shell - Bottom Retainer Screw location
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Tokai Rika Mechanism
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Tokai Rika Shell without Bottom Retainer Screw Hole
My Murakami mirror is still not back together. To see how a primo one should look, look at this forum post
Side View Mirror Repairs
Post #30 by Funkycheeze for a master class on how to rebuild a Murakami mirror.
How to rebuild a Tokai Rika mirror backing plate with drive gears, look from Post 1 by aerojock.
These guys are gods of mirror repairs (among other things).
Dale