it was probably similar to my 1995 toyota truck:

riocar.org photo gallery

on setting it in the frame, there were two side brackets that attached to the frame, and originally held the doodad tray, and the stereo. i put my head unit on the bottom, and just sandwiched the empeg case thingy on the top. it was tight, but it worked out well. it never moved.

i used a dremel on the plastic to make the opening wider, and then a black sharpie to blacken it.