Location of Interior Insulator Piece?

[ed1948]

86 Monte Carlo SS
I took pics of almost every piece I removed 4 months ago except this.......

19" x 10"
I can account for the insulators behind the parking brake assy and behind the ECU kick panel.

 

[oldsmobile joe]

maybe on the upper sail panel, between the quarter window and the back, or rear window?

 

[pontiacgp]

what about the panel on the driver's side that goes from the firewall to the sheet metal piece under the steering column