gf:
I only "wrenched" the Boeing at EAL, but we didn't block out Flaps 40. A couple of times Captains thought it would be nice to let new FOs try a 40 Flap landing. Perhaps, that's why my back hurts in older age. That and the ejection sequence.
The FAA or NTSB recommendation was to use flaps 30 normally, and only use flaps 40 if necessary. TWA elected to block out flaps 40. So far as I know most carriers did not. We flew National 727-200s one or two summers on a summer/winter exchange. They did not have flaps 40 blocked.