Fold Down rear seat back for 67-69 Barracuda

I've found a sweet car I'm considering buying.
It does NOT have fold down rear seat option.

Would appreciate leads to wrecking yards / suppliers for parts to convert non-fold down to fold down.

Even better, would love to buy assembly from someone no longer using rear seat.
I'm near San Diego.
Color / upholstery condition not important.

thanks

Craig