I thought 89 was the last year of the SWB in the us. Maybe yours just squeaked in, cool.
I don't believe the mirrors your looking for were available in the us. They can be found occasionally. The foreign ebay sites can have them. May help if you look for pajero or shogun pillar mirror rather then montero.
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Just need to find one that will ship to you.


1990 LWB RS A/T
1990 LWB Base A/T
1991 LWB LS A/T Going...Going...