OK, Graugeist,
Using your thoughtfully-provided serial number, I found this, which is perhaps where you found the pic? The P-51H test ended in 1952 and that serial number was transferred to the National Guard. I am trying to find a disposition for it out of curiosity only.
Mustang! - Documents
Perhaps you will note the test pilot did not think it was suitable and only 25 landings and takeoffs in total were accomplished with the modified airframe. Also, the P-51H was modified for carrier TAKEOFFS, not for carrier landings. Eventually, even though North American was interested in it, as was the Navy, it was deemed unsuitable. Maybe this was due to the coming of the jet age more than the inability of the P-51 to be "Navalized?" I don't know but it wasn't adopted. Might have been possible with modifications.
So, on the face of this, it would appear the LSO who gave us a talk on it wasn't the LSO on duty for all the landings. I'd say that is probable since the pic is pretty solid evidence.
It doesn't change the fact that Air Force planes are not carrier planes. But it does show that, given suitable incentive, they can be modified to handle a few Navy tasks. It might have been interesting had they proceeded with it. I'd assume the wing would have to have more washout, the stall speed would have to drop some to make Naval margins for arrested landing safety, and the rudder authority would have to improve.
Had they added folding wings, I wonder if it could have been done while simultaneously maintaining performance on the top end. I doubt it, but maybe ...
Perhaps it would have made a good COIN (counterinsurgency) plane. The military investigated those at length in the 1950's - 1960's.
I stand corrected on arrested P-51 landings during a test series.
Good find.
Edit:
If there is anyone out there who knows about these tests, can you tell us if there were any other aircraft on deck in front of the P-51 when it landed, or was the deck empty in case of go around? No reason for asking other than curiosity ... but, if there WERE planes in front of the P-51 then he possibly HAD to make as arrested landing to stop. If there were NO planes in front, he could have landed, rolled out, and stopped. Just curiosity, not a point of argument with anyone.
Usually, when they were doing carrier suitability trials, the deck as empty in case the candidate aircraft bounced and did not catch a wire.
About this point I am wondering if he stopped without being arrested at all ... I wasn't there and, if there WERE planes in front, it would almost HAVE to be arrested. If he lands at 85 mph into a 38 mph wind, he still has to stop from 47 mph deck speed. I have never seen stopping distances for a P-51 on a carrier deck, so I am in unfamiliar territory here.