fe5 red interior

How rare is this on a duster?? My dad's car is a 70 duster 340. Originally it was fe5 inside and out with a black vinyl top and vinyl molding. The body was changed to black back in 1980 and has been that way ever since. Have only seen one other red on red duster and that was in a magazine. Dad's is pretty well loaded up with a/c, rear defogger, 340, auto, pb, ps, tach, bench seat, column shift, deep tint glass, etc. Was just wandering how rare red interior is on a duster, not to mention red on red.