A & G bodies for '78-'88 mid-size GM's are the same platform. The parts (spindles) do interchage/fit. That person in the email you recieved does not know of the GM changing od A toG in '82. As we have noted you'll need to just get the rotors & bearings for the '79-'81 Malibu's to make those spindels work. You could even use '82 & newer rotors (using the '79 & newer bearings as they are the same) but they'll have 12mm wheel studs compaired to the 7/16" studs your Malibu have. Go to
http://www.rockauto.com/ and use their catalog listings to cross reference parts for your car. This fourm will be your best resource to help find & guide you to the parts you can use. I've had my Monte since '90 & found info I didn't know from this fourm.