Another useful tidbit via David Billings.
https://www.youtube.com/watch?v=vgru1mKoHW4 shows Sir Hubert Wilkins arrival in Canada and includes a brief shot of cn1065 that gives us a close look at the patches and fueling ports on the port side of the aircraft. The patches are "scab patches" like the one on NR16020 but they appear to be riveted only around the edges to the internal structure that originally supported the windows. No additional stiffening was needed. The patch on NR16020 was larger and replaced a non-standard window.