I miss understood. I thought you just bought new a arms also, if they are "Blaster" arms they wont fit spindles, they would be somewhat custom. Buying 03+ SPINDLES and using stock arms is still a step back. Going back to drum brakes is stone age $hit.
You need to find out what spindles/brakes you have. Never answered if they are aluminum or iron/steel.
Look on ebay to compare the spindles you have, then contact a arm manufactures to see if they can make a set of arms to fit the spindles you have.