It's a little more complicated than at first it appears. When I wanted to barrel modern Mark X Mauser actions, the smith first Rockwell tested the bottom of the action flat at the front ring, before barreling. Most barrel makers that do rebarrels will test the action hardness first, Pac-Nor being an example.
When I had two old Siamese Mauser actions barreled, these made at the Tokyo Arsenal, Japan, I sent them out for hardness testing and heat treating if needed, but they came back with a report that no heat treating was needed. You may give these folks a try, IIRC they were the company I used.
http://www.industrialheattreat.com/index.html