The size of the machined hole where the bolt/washer goes down is the clue, 3 door ones are MUCH smaller diameter, sapphy 2wd are larger, by around 6mm.
A few very last 3 door had "uprated" heads, ie the larger washer type fitted from new, as did some warranty claim heads on 3 doors.
When roosie got 200 block studded and we fitted the 2wd head we could not find a socket that fitted the nuts that would actually go in the hole, so I ended up machining the socket down, assume this was an early head but didn't measure.
tabetha