According to the owner this was used by merc to figure out how to rig the race boats. It's the same race hull.
Good luck finding history. Rather than bugging the seller (unless you intend to buy it) . . . you might try contacting Parker Rabe
http://www.rabcoboats.com/ and see if he has any knowledge of this hull that he is willing to share.
Randy and Parker's Rabco hull is 28 memco (magnum 27 hull). I'm sure there is a good story as to why they picked the memco/magnum hull over this seacraft hull. I suspect that the magnum27/cigarette28/memco28 lends itself better to be rigged out as a fishing hull. Either way Randy Rabe like the seacraft hull enough to buy it from Mercury for himself. I'm pretty sure contender 21, 23, 25 (28ft) are variations of the magnum hull too.