Blacky wrote:it should have a part number cast into it ???
Thanks Blacky, good advice and based on it I turned the place upside down and can't find the Factory part catalogue cd. Not sure where it is , however I have had a lot of time to surf the net and have come to the opinion that the HR front end is possibly more HK HT HG than HR.
The calipers definitely aren't original- They fit - sorta - hydraulic fitting is in an awkward spot as it is on the base of the hydraulic chamber, so the pipe has to fit from below where the steering arm is uncomfortably close.

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Starting to get a touch peeed off with the guy that sold me this car because most of what he has said has been half truths at best. Perhaps he just didn't know and not willfully ignorant.
The brake pipes I bought for the calipers are useless - too long, angles all wrong and the fittings don't fit as the threads seem off.
Now I am starting to wonder if the HR rotors and pads I bought will have to go on Ebay - From the photos on the net the hubs look like HK Holden, judging by the hex headed bolts.
So a quick remove clean, paint, replace worn bits in turning into a major overhaul.
Oh well have to stop complaining and get on I suppose.