A clarification on carriers for 8.5" ten bolt. Only 2.41:1 and 2.56:1 ratios had different carriers than all other gears.
I'm used to 12 bolts with a few different carriers...
To answer the original question, you can get new gears now. When you get a posi carrier later, swap the ring gear onto the new carrier. Keep track of the shims (left and right), reinstall and you are good to go.