All A12 motors were built at the Lynch road plant and the serial number starts with A9.....
If it does, then you would have to email the A12 web site to check your serial number run. I thought I had had an A12 block since the serial number run fell in between some cars listed on their site but they emailed back saying my motor was out of sequence by 300 or so. Too bad since I have a matching 6 pack intake.