Without checking exact production numbers, a few thousand of the convertibles were made in 58. Might have been something like 2900 of them. According to John Rotellla's http://www.tbirdregistry.com
, there's 112 of these cars known to exist today.
So probably don't ask any more questions, just buy the darn bird and feel very good about yourself. Oh yes maybe one more question, How many 58 converts are in Australia?