Depends on how many miles are on the seats, and how well the interior was maintained. The 60/40's in my '90 have 185k+ on them and the drivers is still in good shape, no sag at all. I have owned it since it was new and had put custom seat covers on it '94. On the other hand my '91 had about 210k miles on it when I got it, it had spent the last 10yrs of its life as a winery truck, no seat covers and the seats were shot to hell, both of them, which is unusual. This set I put in tan '86 I restored in '07 seamed to be a middle of the road, not covered, but taken good care of. W/210k on the odo and w/the exception of a crack in the plastic head rest coating, and a small tear in the vinyl by the back adjuster, the seats were a still solid.
The 3rd gens are little wider than the 2nd gens, but the seats still fit, just less room between them and the doors, than w/the 2nd gen seats. As with most import seat swaps, the outer mounts line up, the inner front does as well(if set-up for buckets), and the inner rear mount lines up w/the seat belt bolt. IIRC, I used the seat belt bolt for both the belt and the seat mount. In order for the seats to sit level, you will have to raise the outer rear mount a little, about 3/8-1/4" if I remember correctly, which seams to be common for most bucket seat swaps, at least those that I have done in the 2nd gens.
A set of 1st gen Tacoma seats should still fit about the same, I can't comment on any other manufacturer seats.
