I tried out various methods to allow me to keep the vanilla 10.8.2 AppleACPIPlatform.kext. The solution was quite easy and had a nice benefit to it. I installed Kozleks branch of FakeSMC + optional Kexts for sensors:
Not only can I now boot with the original 10.8.2 AppleACPIPlatform.kext, without having OemSMBIOS.kext throwing an error, but I also get much more information from my hardware sensors opposed to the original FlakeSMC-Plugins I had been using. Furthermore a serial number is generated for my machine (so no problems with iCloud and Appstore) and VT-d can stay enabled in BIOS!
Using the kexts from Kozlek was a win-win for me - thanks Kozlek!!!
Thanks. I tried this and the update went smoothly. I didn't have to replace anything....and I no longer have problems with the Appstore.