I'm pretty sure that there were only something like 500 or so made unsure of the exact build date's but I think it was like March April in 75 I think, I may well be wrong.
Have a look at it plate's under the bonnet they should give you the exact date, week and which line they came off.
If not get on to the Falcon Cobra Car Club of Australia web site and send Mark Pividor an e-mail he seem's to know a lot about the Goss' as well as the Cobra's.
p.s my missus will be very envious of you, she's wanted a John Goss special for ages, but we just can't seem to find any for sale.
351 mate, the last of the big V8's
Grand daddy of Sport's car's