Here's a couple of data points for you.
I got an unfired, previously owned .40 Pro, 4.25" with night sights, two standard magazines, case and back straps last month in Loveland, Colorado. The price on the tag was $580. (I actually did a trade for the Pro .40.)
As I recall they did have a NIB 9mm Pro equipped the same for $600.
It was interesting, they had the two Pro Series pistols on the shelf and a standard FS .40. All three were gone in about 30 minutes. It wasn't like they just put them on the shelf, or they just opened, three buyers were there at the same time.
Bill