Hi Alex. For reference these are the main countermeasure (mostly jamming) systems as would be used by the 8th/12th/15th AFs; mostly by the Eighth .Their equivalent of the 16th was a Radio Countermeasures Sqn , the 36th BS (RCM) formerly in the Eleventh AF.
Their equipment at the end of 1944 was Mandrel, Jostle, Dina, ELINT, Jackal and Carpet. I don't recall them using the term "Ferret" for their aircraft.
Looking at the photo of 437 again I think it's more likely to be a thin coat of black over the Olive Drab for night operations; the RAF had found that a disruptive pattern was more effective than solid colour on moonlit nights for their night fighters, but the RCM and Night leaflet Sqns. in the UK used overall or partly black finishes (their Gloss Black was very effective against searchlights).
Nick
https://www.qsl.net/pe1ngz/airforce/...f-jamming.html