The serial number you list indicates that the car is the 1,145th 1951 6 cylinder HJ built; serial numbers in 1951 started with 001001. According to the factory numbers I have for production, the serial number indicates the car came off the line around the middle of August, 1950, about 6 weeks or so before public introduction date.
The original dealer ordering information indicates that the only greens initially offered were the non-metallic Ceramic Green and the lighter Aloha Green (your roof and rear deck. Paint numbers on the Body Tag (near the driver side hood hinge at top of the firewall corner) would tell more about original color, etc. Other numbers on this tag would identify the original upholstery material, verify transmission type (3-speed manual or 3-speed with overdrive) and other aspects of the car. Also, the separate body serial number (smaller plate by the Body Tag) would further verify line position.