Yep my external regulator sat in the bay for a while till I trusted
the modifications over the years then eventually removed it and shortened
the wires that were connected to rid the external reg.

Japan maybe improved the quality of their later internally regulated alts
on fwd engines maybe from the extra heat and improved know how as japanese
economy improved and exports increased out of Japan.

My Mazda 70s alternators died from living over 7000rpm but when replaced
with later 80s units one I know has had engine rebuilt halve a dozen times
but alternator is the 90s version upgrade I had done which the auto elec
just charged me a 4L Cask of Lambrusco. It was just a wire with connectors
that joined 2 pins and to check the charging voltage etc.
For me at the time it was like he knew how to do magic :)