Send through the plate info purely for our database records.
Everyone is correct - real value is determined by the purchaser and how much the seller will agree on to sell.
A couple photos of exterior and interior would be very helpful as we could provide some advice on how 'original' it really is.

I've had people say they have an original untouched factory HX Sandman, and it turns up with HJ mirrors, gts guards and quad light nose cone. 40 years is a long time in car history