Shouldn't the Generic AHCI entry match on class code here?
System Profiler detail is often largely cosmetic, although there are SATA injector .kexts for specific chipsets. In this same Dell Precision 690 I have a Marvell eSATA card which is normally picked up as GenericAHCI but I've injected correct details into a legacy .kext residing in /S/L/E:
I think I'm right in saying that the Info.plist in DP3 AppleAHCIPort.kext and that for DP2 and earlier are identical, however my suspicion is that the binaries may not be - unless the difference is somewhere else in the AHCI disk chain.
I no longer have DP2 or DP1 installed to diff and check.