[Mr70]

That's a Stereo Multiplex under the Dash.Early units had a 4th far right Dummy knob.
The Vinyl Top was not inclusive of the Z16 package.Most did have it ordered,but some did not.BoB Macy,Roger Ausley,Richard Fudge,Floyd Garrets,all have/had Z16's w/o VTop.
I emailed the seller.
"This Car was built with a Vinyl top,but was restored without it.Just thought it looked better,and buyer can have the metal trim peices for it if wish."
He also says this is the ORIGINAL Engine in this Z16, Vin#5K117209 stamped on the Pad.
He Has pix from 1991 showing it before resto.