@Mike G. brings up a good point. Let me start by saying I don't do rehabs. When I think of the marketing of a property though, does a prospective buyer "want" to know how bad of condition a property was in before the rehab?
Putting myself in a buyer's shoes, I would be more likely to run, or at best, offer way less on a property that I knew was in really bad shape a few weeks before. How do I know what is behind the drywall and new paint? Under the new laminate floors?
I'm always amazed at the TV shows on flipping where they show the people selling the house after the rehab and they're explaining to the prospects how bad the house was before they just fixed it up. You can see most of the buyers visibly move their head back a little like "That's bad, why did you tell me that?"
If I was buying a restored 1949 Oldsmobile I would want to see the before and after because I expect something that old to have gone from bad to good. If I'm buying a 1979 ranch, I'm not so sure I want to see the grungy bathroom and stained ceiling before photos - or even told how bad it was.
I understand from the rehabber side that you're proud of the work and it's cool to show off how bad something was before and how great it looks now, but should a buyer be told how bad it was? If they ask, yes then full disclosure, but should it be volunteered?