I spent 15 months renovating a 3A and the plans called for metal straps that the pins clamp onto, to be heat treated so I grabbed one of the four and took it to a local engineering business to have it "Rockwell" tested. If I remember right it came back with a result (70,000 psi?) that definitely showed it had been heat treated, so I made the assumption that the original builder had also done that to the other three pieces. I enjoyed the process of getting it flying again after it sat for 12 yrs., but the real kick was actually flying it!
Doug Lomheim
RV-3A sold
RV-9A Mazda 13B/FWF