Thats right Mildman,i think it,s differant in most states,but up here if it,s over 30 years old you apply for"special interest" rego once your club rep has sighted the car he then issues you a letter stating the vehicle complies within the spirit of things along with relevent body and chassis numbers then off you go to waste half a day at the rego department.
It may be simpler if"down grading"from full reg to "s"(club)plate reg but you would still need the letter from the club.