Not at all. The factory electric locking differentials are cool, but are certainly not the only option. I think the estimates are somewhere between 10-15% of FZJ80s came with them from the factory. It is still a great platform if you're looking for something in that size. You can always add aftermarket lockers later if you decide that's what you need.
$1900 does sound like a great deal, but it may not end up to be so sweet if you need to sink a lot of money into unplanned maintenance and repairs. Realize that you are not buying parts and maintenance for a $2000 vehicle - you are buying parts and maintenance for a $50,000 vehicle that is now 16 years old. Do some research and know what you're getting into:
http://www.sleeoffroad.com/newbie/newbie100.htm
http://forum.ih8mud.com/80-series-tech/
Good luck.