I just remember the telephone conference, where AMD talked about AM3+.
They said that they needed some new electric stuff for the last +5% extra performance. Because Bulldozer is an enthusiast CPU, and enthusiast want any extra performance, they decided to have AM3+.
An AM3 Bulldozer design is no problem, it will just have ~5% less performance.
Maybe they changed their opinion since then, who knows. There is a new (temporary) CEO, maybe he is more in favor of upgradeablility ?
However, I currently think that it is MSI's error. They use the same basic PCB Design for the GD70/GD65 and the upcoming BingBangConqueror AM3+ board with 990FX chipset.
All boards are from the 7640 series, the GD70 is with the additional markings "ver 1.2" oldest, the GD65 with ver. 3 is newest, and the (real) AM3+ board is in between with ver 2.0.
Quite likely that somebody forgot to delete the AM3+ string from the previous design.
However, one has to wonder what the MSI people are blabbering then about AM3+ compatibility
In any case, we will have confirmation in a few hours, thanks @newls1 for checking 
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