As far as I know, Gerber doesn't have numbers or dates for their MP600 variants (I've asked). I'm not even sure Gerber has a list of all their variants, there are so many that almost seem to be one offs (maybe remnants of the Customized MP600 program?).
The blunt nosed variants are certainly earlier in the Pro Scout production, but dates will be impossible to find I suspect. And I agree, technically drop point so called "Pro Scouts" aren't called that (bu no one knows what that variant is called!), so I say just call them pro scouts and be done with it.
Also, $30 for an MP600 in decent is a great deal, especially for one of the rarer flavors!