Well, I took the gun out and shot a round of sporting clays today. All went well with no Failures to fire. The dimples on the primers looked identical to each other (left and right barrels). Great feeling.
I took David's suggestion and did not heat treat it. If I need another, I still have 34" of drill rod and then I will heat treat.
I did learn that when you file metal it gets hot and when metal gets hot it expands. My precise measurements shrunk when it cooled but it still worked.
I set a 2" piece of drill rod in an electric drill and placed it horizontally in a vise. With a few different files I spent an hour or so filing and measuring. I quickly learned it was a lot easier to place the file under the pin to keep a better eye on it. I enjoyed watching the filings march down the file as I progressed. Using the edge of the file to start helped also, especially on the mid belt.
Thank you all for taking the time and interest to advise me with enough info to get the job done. I have done a lot of wood work but little with metal (as some of you have guessed based on my handle or profile).