unexpanded A1200 has 68020, thats right. so it should work. one problem i see is the harddisk installation. in one of the texts they talk about A500/2000 and A3000 and compatible harddisk-controller. the harddisk controller of the A1200 is for sure different (A3000 has scsi) - so the harddisk installation might not work.
but give it a try and report back