I think they were all press on by the 80s. The press on really is a better way to go. If you really want a keyway pump I know I pulled one from a 73 chevy truck once. Not sure when they went to the prees on style.
I've been told that the early 80's AMC's had wide v-belt pulleys... not sure if they were press/keyway... Even if I stick to press, I want to run the widest belt possible (21/32" on a OEM FJ40)