I contacted LMC and they confirmed that they sell the factory style parking brake release rod and the stake on type handle.
I already had purchased a threaded handle (from Classic Parts, AIRC), so I decided to try to thread my existing rod with a 12-24 die. This was my first use of a die for the purpose of threading smooth rod (I previously only used a die for chasing threads - wrong, I know - but I do it anyway.)
I used a file to smooth off the staking lugs and tried the die. I could not get a good bite at first so I had to file off a little extra metal, then I could get the threads cutting. Good thing I had a high quality $10 Harbor Freight tap and die set.
I added a nut to help stop the handle from turning.