A53 car a Barrett-Jackson tomorrow

So...based on what the Formula- S 383/727 went for at Barrett-Jackson, what do you think a '69 383/4-speed (1 of 333) is worth?
Several of us from Inland Mopars just got through detailing one of our fellow member's car to show in our club display at the upcoming Grand National Roadster Show at the Fairplex in Pomona Jan. 25-27. All stock, including the hubcaps, except for a dual-quad setup and a bright red re-paint. He has the stock 4-bbl carb and intake.
Reason I'm asking is it may be for sale in a year or two as he can no longer drive because of the early stages of Altzheimer's. We made sure to get his pretty Formula-S in the GNRS show while he can still enjoy it.
I'll post pics after the show if anybody may be interested.