I just did this as one of mine bent in my KE15 when i was traveling at 110kmh! (interesting experience)
There is a guy in clayton victoria, mechanic with tonnes of old corolla parts, i cant give u a name or address or phone number (what a help i am) but he helped me out with mine when i needed them, someone on these forums SHOULD know his name and number (ive got his card here but its faded!)
He said that they came with 2 different sized threads on the rods etc, but if u can get a hold of him he should be able to help you with replacements