I went by my local Z-junk yard today to look at some replacement seats. i found some in good condition just a little dirty. They are black vinyl and look exactly like the type found in the 71 Z (horizontal stiching with 4 metal vents), except these do not have the 4 metal vents. The seats are not firm like my butterscotch vinyl seats, the vinyl feels softer, and a little bit less brittle. How can i tell if they are original upholstery? i do not know the year of the car.

Is there original upholstered vinyl seats with no vents at the bottom?

A qualified no. The original upholstery for a '71 model year American import (HLS30) car had metal vents.

Snap a photo if you can. what sort of price are they?

these are not from a 71 Z. the guy told me it was a 72 or 73 but was not sure even of that.

They are selling for 40 bucks each, reguardless of condition. He will even sell me the original upholstered seat with vents for 40 bucks, but not the right color i want. This guy sells all his stuff for cheap..

.. I picked up great condition interior door panels from a 78 Z for 40 bucks a pair. fuel pump 15 bucks, windshield 40 bucks, arm rests 20 for a pair, good running engine for 300. He just drinks beer all day long and runs a paint n body shop