I would agree with that amount.
Probably closer to the 10k for an OEM grade turnkey resto.

Here's what needs to be gone through evaluated, stripped, refinished, rebuilt or replaced.

Dash pad
Dash frame
Dash lower trim
Radio
Speakers
Wiring
Ash tray
Glove box
Light bar
Gauge rebuild
Gauge refacing
HL, Wiper, Dimmer, Fan Switch rebuilds
Gauge pod
Cluster Lens
Woodgrain bezel and backing plate
Heater or A/C control
Misc.based on options: Rear fader, glove box light, ash tray light, 4spd reverse light, Map light etc.