Like Larry said, these usually have the transport on top and two mono tube amps on the bottom with "doors" on the side to open for the speakers.
If the one you are looking at has external cabs are the made by Akai? I could not see them being worth anything as added value really unless you were an Akai collector (unless they are JBL's, Tannoy's, Altec.....)
Working unit in nice condition usually sell for $50-100. I've never paid over $50 for one. I had 4 set of mono blocks but sold two recently to fund two other families Christmas'.
What are they asking for it?