Curious Question with WD

[pclab]

Hi

I have a WD that needs head swap.
I have ordered a donor.
Details:

Pacient: WD15EARS-00S8B1
Date: 25 Aug 2010
DCM: HARNHT2AAB
Thailand

Donor:WD15EARS-00S8B1
Date: 01 Jun 2010
DCM: HBNNHT2AAB
Thailand

What's weird: I checked head map and on pacient it says:
8 heads - 0,1,2,3,4,5,6,7
On donor:
8heads - 7 in use
0,1,2,3,5,6,7
Why the difference? Will the heads be compatible? I know I have to test but...
Thanks

[AJ2008]

Head is present but only disabled, it will still be good as a donor.