Likely the outer two mounts of the seats will bolt up, but the inner ones wont.  Also the 3rd gens are wider than the 1st gen, and the seats wont fit as well.  The last 4x4 I rebuilt for sale, I put these 3rd gen 40/60 buckets into an '86.  They fit, but it was tight, not a lot of room to adjust the seats with the door closed.

As mentioned you can pretty much fit any bucket seats into any vehicle, it just depends on how much fabrication work you are able to do.

The normal rule of thumb is to look for seats from the same manufacturer and same era as yours, i.e., celica. supra, maybe camry seats would fit better in the '80, then the mid to late '80's and so on.  Also other imports from the same/close to the year will work with little effort.

I would start off by putting the seats in where the line up with the steering wheel, then see where they line up with the mounts, you cam always drill new mounts(just reinforce them plate steel or large washers).

One other issue with seats, is they usually aren't level, and usually require some shimming of the outside rear mount.  Sometimes it takes only a few washers, other times it takes welding an extension.  Since they are Toyota seats it should only be a few washers.