A search of the web found discussion board postings which appears to be copied straight from Chinese PLAAF publications. One revealed that the Aug. 9th, 1952 action involved 8 MiG's. One flight of 4 from the 18th Air Division (AD)/52nd Air Regiment (AR) led by the deputy regimental commander Zhang, Chuan-zhi claimed one kill against "F-Mk8" while covered by another 4 led by the deputy commander of the 3rd AD/7th AR Sun, Jing-Hua.
Thanks,
This?:
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It's also on the official 50th anniversary KW Chinese chronology I copied from the web a long time ago but never noticed (perhaps because my Chinese reading stinks

though a little less now than it did at the time). It seems to say 8 and 8 a/c of 18/52 and 3/7 for 2 victories over 'FMK-8's'
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(only the google-cache version seems to ever come up now)
To compare this back to the 802 sdn diary excerpted in Landsdowne p 273-4:
0630 15 mi N of Chinnampo (Nampo) Carmichael's flight of 4 Sea Furies sighted 8 MiG's. 4-5 minute dogfight, where all four FAA pilots fired and at least 3 reported registering hits in 'a dozen of so firing passes', mainly head on; though one pulled in front of SubLt BE Ellis on an overshoot, and was reported by him to disengage 'at reduced speed' with two other MiG's covering it after being hit in the wings. No specific MiG seemed to be followed from hit to crash, but rather as the MiG's departed an aircraft was seen to crash, feared to be a Sea Fury but when all 4 pilots reported in OK assumed to be a MiG. Claim 1 dest/0 prob/2 dam. 'from a confused situation Carmichael as flight leader got the credit for its destruction'. Although, a quote from Carmichael on p 275 somewhat contradicts the sdn diary by saying he was sure he got the MiG and followed it from hit to crash.
0800 'a report came through' that Lt RJ Clark's Sea Fury, of another flight, was hit in the right wing and caught fire. He put the fire out by sideslipping and returned safely. Lt HM McEnery of the same flight claimed a MiG damaged.
"by the time Clark returned" Lt. RH Hallam's flight was attacked. "Hallam was leading a weaving procession of 1 Sea Fury, 2 MiG's and 1 Fury down the Taedong Gang (river)...Hallam was obliged to make a wheels up landing on Chodo...large hole just behind the cockpit where a 37mm had found its mark".
So, there were three separate actions with at least the first two possibly too far apart in time to be the same MiG's. In any case since Sea Furies were hit in the second two encounters, odds are those are the ones which make up the 2 'FMK-8' claims. It seems possible the first could have been a different unit or different a/c of the same unit but in any case I agree with your implication that the lack of mention of losses in the brief official account doesn't mean much. Pretty heavy overall PLAAF MiG losses in Korea are acknowledged in total, but specific accounts seem to emphasize covering the claims.
One more source to throw out in Zhang in "Red Wings Over the Yalu" p 190 gives the claim for PLAAF fighter bomber hunting south of Pyongyang in July-Oct 1952 as 30 UN a/c (jet and naval prop) for 2 MiG's destroyed. His footnote is partly to I believe the same book you mentioned, though he transliterates the spelling differently.
Anyway now I've learned some more about this incident, and I hope at some point we get still more details from the MiG side.
Joe