Mustang seats, and looks like the dashpad is red or orange in a previous life...trunk spoiler screams FURD!!! Take it off!
One option (could have been added at a later time, not originally) is the center console. Only the data plate or broadcast sheet will tell the true story. Have you pulled the carpeting, rear seat and package shelf to see if any sheets are underneath?
Whats the VIN tag on the dashpad say? If it starts with BS, thats a Cuda, if BH, thats a Barracuda. If not there, look for it on the drivers door jamb, it might have been painted over, carefully remove the paint to reveal the door tag.
Keep us posted what you find out!