The Planes of Fame flies the oldest Corsair still flying. It started life as an F4U-1, was upgraded to F4U-1a, and then to F4U-1d.
The -1 was a "birdcage" canopy.
The -1a had a 3-piece canopy with two canopy support across the canopy fore and aft near the top of the canopy.
The -1d had a 1-piece, full blown canopy, with no interfering supports in the plexi area.
Those are not the ONLY changes, but are the easiest from which to make an identification.
From what I have heard (from ONE corsair pilot), the aircraft has a "mind of its own" when landing at standard gear service values. That is, you never know which way it will go (left or right) when the main gear touches down and have to be on top of it. Since we are NOT in the Navy and not at war hauling ordnance, we typically operate it at about half of the strut pressure called for in the tech order, and it tracks decently when landing. I understand it failed carrier suitability when it was tested by the U.S.A., but the British didn't "fix it," they just operated it from carriers successfully by figuring out how to do that in a manner safer than a then-standard approach.
That, in turn, embarrassed the Navy and they decided that the Corsair was carrier-suitable since it was being flown from British carriers. It wasn't a case of it not being suitable as much as it was a training thing. By adjusting the landing pattern, you could see enough to make operations safer. The British had the attitude of "figure out how to operate this thing from a carrier," and we had the attitude, "does it pass the standard carrier-suitability test?".
So, I don't believe they made any "fixes." Instead, they figured out how to modify the approach so it was at least safer than a straight-in approach. They MAY have figured out a stall strip on one wing root and it may have been us that figured that out; I can't recall just now, but the main fix was never a mechanical fix; it was an operational change to the standard landing pattern more than anything else. That from several former Corsair pilots who gave regular talks up until several years ago. Basically, we haven't had too may WWII vets give talks since the pandemic, and most of the ones I have known have passed away in the last few years, as we might expect.