Historically speaking the indicator stalk was always on the opposite side from the gearstick, however American/European manufacturers decided (at various points in time each, but it really kicked off in the early 90's) that the was no point bothering to make extra RHD stalks just for the UK, Australia and a couple of other markets so those countries could just use LHD stalks and like it.
It became so widespread that even British manufacturers started to put them on the same side as the gearstick and eventually Japanese makers started to do it for their UKDM cars too.
And I for one hate it with a burning passion lol.
90s? Try 60s/70s, I've driven loads of 70s cars and all have the indicator to the left of the column.