800 was about correct for a delivered NIB Redhawk 5 years ago. The .45s were one of the later runs, I seem to remember the 4" ones were all built after 2000, with a switchover from the pinned from sight to the replaceable dovetail around 2010 or so.
Auction price might hit 1200 with the right bidders, 900-1000 is probably more realistic. None of the Redhawk cartridges are growing on trees right now, so demand is somewhat suppressed IMO.