Audio Systems: 1988 chevy 1500 ac delco unit, 1988 chevy 1500, ac delco

Question
I have an 88 chevy 1500 and whoever owned it before me unhooked the stock radio and hacked a hudge unit in the middle of the dash.  Im not sure if it originally had a separate tapedeck option or not, the only party left is the head.  I understand that year was a three piece unit. Is that correct? Or can I possibly hook the head unit direct.  The problem I see is that any wiring harnesses to the stock unit look to be bypassed and I also dont see a antennae hook up on the head unit.  HELP!!!!

Answer
Yes, it had a three part system. No it's not worth putting back to stock. You will just need a dash kit, and antenna adaptor, and a power harness adaptor, if the plug has not yet been butchered. The original connections were plugged into a silver box above the gas pedal.