Update and success!
The chrome surrounds and electric motors are identical between the 70 series and the 62. The only difference is the base, but I can now confirm that you can swap the bases from your 62 onto the 70 series mirrors.
The tools required are a properly sized (this is very important) Phillips head screw driver, a pick (to disconnect the wires from the clip so you can feed it through the base), and some patience.
Note that the screws holding the 70 series bases on are very soft and are in VERY good with thread locker. I am still working at extracting one that stripped from the passenger side (see photo), but the driver side is fully assembled and working very well.
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